binder: move binder_alloc to separate file

Move the binder allocator functionality to its own file

Continuation of splitting the binder allocator from the binder
driver. Split binder_alloc functions from normal binder functions.

Add kernel doc comments to functions declared extern in
binder_alloc.h

Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/android/Makefile b/drivers/android/Makefile
index 3b7e4b0..4b7c726 100644
--- a/drivers/android/Makefile
+++ b/drivers/android/Makefile
@@ -1,3 +1,3 @@
 ccflags-y += -I$(src)			# needed for trace events
 
-obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder.o
+obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder.o binder_alloc.o