powerpc: make ARCH=ppc use arch/powerpc/kernel/process.c

Commit 5388fb1025443ec223ba556b10efc4c5f83f8682 made signal_32.c
use discard_lazy_cpu_state, which broke ARCH=ppc because that
uses the common signal_32.c but has its own process.c.  Make ARCH=ppc
use the common process.c to fix this and to reduce the amount
of duplicated code.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 913f906..9101358 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -223,6 +223,7 @@
 }
 #endif /* CONFIG_SMP */
 
+#ifdef CONFIG_PPC_MERGE		/* XXX for now */
 int set_dabr(unsigned long dabr)
 {
 	if (ppc_md.set_dabr)
@@ -231,6 +232,7 @@
 	mtspr(SPRN_DABR, dabr);
 	return 0;
 }
+#endif
 
 #ifdef CONFIG_PPC64
 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);