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>
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 3fcac3c..a4ceb9a 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -746,6 +746,7 @@
  * any task or sent any task a signal, you should use
  * ret_from_except or ret_from_except_lite instead of this.
  */
+	.globl	fast_exception_return
 fast_exception_return:
 	ld	r12,_MSR(r1)
 	ld	r11,_NIP(r1)