powerpc: Remove the empty giveup_fpu() function on 32bit kernel

Instead of implementing an empty giveup_fpu() function for each
32bit processor type, replace them with an unique empty inline
function.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
index 39cf0f6..2c7edde 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -16,7 +16,6 @@
 extern struct task_struct *_switch(struct thread_struct *prev,
 				   struct thread_struct *next);
 
-extern void giveup_fpu(struct task_struct *);
 extern void load_up_fpu(void);
 extern void enable_kernel_fp(void);
 extern void enable_kernel_altivec(void);
@@ -38,8 +37,10 @@
 
 #ifdef CONFIG_PPC_FPU
 extern void flush_fp_to_thread(struct task_struct *);
+extern void giveup_fpu(struct task_struct *);
 #else
 static inline void flush_fp_to_thread(struct task_struct *t) { }
+static inline void giveup_fpu(struct task_struct *t) { }
 #endif
 
 #ifdef CONFIG_ALTIVEC