docs: early-userspace: move to driver-api guide

Those documents describe a kAPI. So, add to the driver-api
book.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
diff --git a/Documentation/early-userspace/buffer-format.rst b/Documentation/driver-api/early-userspace/buffer-format.rst
similarity index 100%
rename from Documentation/early-userspace/buffer-format.rst
rename to Documentation/driver-api/early-userspace/buffer-format.rst
diff --git a/Documentation/early-userspace/early_userspace_support.rst b/Documentation/driver-api/early-userspace/early_userspace_support.rst
similarity index 100%
rename from Documentation/early-userspace/early_userspace_support.rst
rename to Documentation/driver-api/early-userspace/early_userspace_support.rst
diff --git a/Documentation/early-userspace/index.rst b/Documentation/driver-api/early-userspace/index.rst
similarity index 95%
rename from Documentation/early-userspace/index.rst
rename to Documentation/driver-api/early-userspace/index.rst
index 2b8eb61..6f20c3c 100644
--- a/Documentation/early-userspace/index.rst
+++ b/Documentation/driver-api/early-userspace/index.rst
@@ -1,5 +1,3 @@
-:orphan:
-
 ===============
 Early Userspace
 ===============
diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst
index baa77a6..0f281f4 100644
--- a/Documentation/driver-api/index.rst
+++ b/Documentation/driver-api/index.rst
@@ -16,6 +16,7 @@
 
    basics
    infrastructure
+   early-userspace/index
    pm/index
    clk
    device-io
diff --git a/Documentation/filesystems/nfs/nfsroot.txt b/Documentation/filesystems/nfs/nfsroot.txt
index 4862d3d..ae43324 100644
--- a/Documentation/filesystems/nfs/nfsroot.txt
+++ b/Documentation/filesystems/nfs/nfsroot.txt
@@ -239,7 +239,7 @@
   A description of the process of mounting the root file system can be
   found in:
 
-    Documentation/early-userspace/early_userspace_support.rst
+    Documentation/driver-api/early-userspace/early_userspace_support.rst
 
 
 
diff --git a/Documentation/filesystems/ramfs-rootfs-initramfs.txt b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
index fa98590..97d42cc 100644
--- a/Documentation/filesystems/ramfs-rootfs-initramfs.txt
+++ b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
@@ -105,7 +105,7 @@
   - The old initrd file was a gzipped filesystem image (in some file format,
     such as ext2, that needed a driver built into the kernel), while the new
     initramfs archive is a gzipped cpio archive (like tar only simpler,
-    see cpio(1) and Documentation/early-userspace/buffer-format.rst).  The
+    see cpio(1) and Documentation/driver-api/early-userspace/buffer-format.rst).  The
     kernel's cpio extraction code is not only extremely small, it's also
     __init text and data that can be discarded during the boot process.
 
@@ -159,7 +159,7 @@
 set permissions or create device nodes in the new archive.  (Note that those
 two example "file" entries expect to find files named "init.sh" and "busybox" in
 a directory called "initramfs", under the linux-2.6.* directory.  See
-Documentation/early-userspace/early_userspace_support.rst for more details.)
+Documentation/driver-api/early-userspace/early_userspace_support.rst for more details.)
 
 The kernel does not depend on external cpio tools.  If you specify a
 directory instead of a configuration file, the kernel's build infrastructure
diff --git a/usr/Kconfig b/usr/Kconfig
index 86e37e2..a6b6850 100644
--- a/usr/Kconfig
+++ b/usr/Kconfig
@@ -18,7 +18,7 @@
 	  When multiple directories and files are specified then the
 	  initramfs image will be the aggregate of all of them.
 
-	  See <file:Documentation/early-userspace/early_userspace_support.rst> for more details.
+	  See <file:Documentation/driver-api/early-userspace/early_userspace_support.rst> for more details.
 
 	  If you are not sure, leave it blank.