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/include/asm-ppc/system.h b/include/asm-ppc/system.h
index bd99cb5..b970373 100644
--- a/include/asm-ppc/system.h
+++ b/include/asm-ppc/system.h
@@ -4,7 +4,6 @@
 #ifndef __PPC_SYSTEM_H
 #define __PPC_SYSTEM_H
 
-#include <linux/config.h>
 #include <linux/kernel.h>
 
 #include <asm/atomic.h>
@@ -39,7 +38,7 @@
 #ifdef CONFIG_SMP
 #define smp_mb()	mb()
 #define smp_rmb()	rmb()
-#define smp_wmb()	wmb()
+#define smp_wmb()	__asm__ __volatile__ ("eieio" : : : "memory")
 #define smp_read_barrier_depends()	read_barrier_depends()
 #else
 #define smp_mb()	barrier()
@@ -74,6 +73,7 @@
 extern void read_rtc_time(void);
 extern void pmac_find_display(void);
 extern void giveup_fpu(struct task_struct *);
+extern void disable_kernel_fp(void);
 extern void enable_kernel_fp(void);
 extern void flush_fp_to_thread(struct task_struct *);
 extern void enable_kernel_altivec(void);
@@ -86,6 +86,14 @@
 extern void cvt_fd(float *from, double *to, struct thread_struct *thread);
 extern void cvt_df(double *from, float *to, struct thread_struct *thread);
 
+#ifndef CONFIG_SMP
+extern void discard_lazy_cpu_state(void);
+#else
+static inline void discard_lazy_cpu_state(void)
+{
+}
+#endif
+
 #ifdef CONFIG_ALTIVEC
 extern void flush_altivec_to_thread(struct task_struct *);
 #else