powerpc: Move include files to arch/powerpc/include/asm

from include/asm-powerpc.  This is the result of a

mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm

Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly.  Of the latter only
one was outside the arch code and it is a driver only built for powerpc.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/char/hvcs.c b/drivers/char/hvcs.c
index 786d518..473d9b1 100644
--- a/drivers/char/hvcs.c
+++ b/drivers/char/hvcs.c
@@ -114,7 +114,7 @@
  * the hvcs_final_close() function in order to get it out of the spinlock.
  * Rearranged hvcs_close().  Cleaned up some printks and did some housekeeping
  * on the changelog.  Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from
- * include/asm-powerpc/hvcserver.h 
+ * arch/powerepc/include/asm/hvcserver.h
  *
  * 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to
  * prevent possible lockup with realtime scheduling as similarily pointed out by