powerpc: Export msr_check_and_set() to modules

PR KVM will need to reuse msr_check_and_set().
This patch exports this API for reuse.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/process.c

@@ -154,6 +154,7 @@ unsigned long msr_check_and_set(unsigned long bits)
 
 	return newmsr;
 }
+EXPORT_SYMBOL_GPL(msr_check_and_set);
 
 void __msr_check_and_clear(unsigned long bits)
 {