kbuild: drop include2/ used for O=... builds

There is no longer any use of the include2/ directory.
The generated files has moved to include/generated.

Drop all references to said directory.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
diff --git a/Makefile b/Makefile
index eb43b9fa..b9d747e 100644
--- a/Makefile
+++ b/Makefile
@@ -335,7 +335,7 @@
 # Use LINUXINCLUDE when you must reference the include/ directory.
 # Needed to be compatible with the O= option
 LINUXINCLUDE    := -I$(srctree)/arch/$(hdr-arch)/include -Iinclude \
-                   $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include) \
+                   $(if $(KBUILD_SRC), -I$(srctree)/include) \
                    -include include/linux/autoconf.h
 
 KBUILD_CPPFLAGS := -D__KERNEL__
@@ -954,7 +954,6 @@
 # prepare3 is used to check if we are building in a separate output directory,
 # and if so do:
 # 1) Check that make has not been executed in the kernel src $(srctree)
-# 2) Create the include2 directory, used for the second asm symlink
 prepare3: include/config/kernel.release
 ifneq ($(KBUILD_SRC),)
 	@$(kecho) '  Using $(srctree) as source for kernel'
@@ -963,10 +962,6 @@
 		echo "  in the '$(srctree)' directory.";\
 		/bin/false; \
 	fi;
-	$(Q)if [ ! -d include2 ]; then                                  \
-	    mkdir -p include2;                                          \
-	    ln -fsn $(srctree)/include/asm-$(SRCARCH) include2/asm;     \
-	fi
 endif
 
 # prepare2 creates a makefile if using a separate output directory
@@ -1193,7 +1188,7 @@
                 .tmp_kallsyms* .tmp_version .tmp_vmlinux* .tmp_System.map
 
 # Directories & files removed with 'make mrproper'
-MRPROPER_DIRS  += include/config include2 usr/include include/generated
+MRPROPER_DIRS  += include/config usr/include include/generated
 MRPROPER_FILES += .config .config.old include/asm .version .old_version \
                   include/linux/autoconf.h include/linux/version.h      \
                   include/linux/utsrelease.h                            \