[PATCH] powerpc: remove arch/powerpc/include hack for 64 bit

With the removal of include/asm-powerpc, we no longer need
arch/powerpc/include/asm for the 64 bit build.  We also do not need
-Iarch/powerpc for the 64 bit build either.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>