[PATCH 1/2] powerpc: add enable_kernel_fp() stub for ALTIVEC without PPC_FPU

On a kernel config with ALTIVEC=y and PPC_FPU not set/enabled,
there is a build error:

drivers/cpufreq/pmac32-cpufreq.c:262:2: error: implicit declaration of function 'enable_kernel_fp' [-Werror,-Wimplicit-function-declaration]
           enable_kernel_fp();

so add a stub function for that when PPC_FPU is not set.

Signed-off-by: Randy Dunlap <redacted>
Reported-by: kernel test robot <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Christophe Leroy <redacted>
Cc: Segher Boessenkool <redacted>
Cc: lkp@intel.com
---
 arch/powerpc/include/asm/switch_to.h |    1 +
 1 file changed, 1 insertion(+)

--- linux-next-20210416.orig/arch/powerpc/include/asm/switch_to.h
+++ linux-next-20210416/arch/powerpc/include/asm/switch_to.h

@@ -48,6 +48,7 @@ static inline void disable_kernel_fp(voi
 #else
 static inline void save_fpu(struct task_struct *t) { }
 static inline void flush_fp_to_thread(struct task_struct *t) { }
+static inline void enable_kernel_fp(void) { }
 #endif
 
 #ifdef CONFIG_ALTIVEC