powerpc: Get 64-bit configs to compile with ARCH=powerpc

This is a bunch of mostly small fixes that are needed to get
ARCH=powerpc to compile for 64-bit.  This adds setup_64.c from
arch/ppc64/kernel/setup.c and locks.c from arch/ppc64/lib/locks.c.

Signed-off-by: Paul Mackerras <paulus@samba.org>