ARM: prefetch: remove redundant "cc" clobber

The pld instruction does not affect the condition flags, so don't bother
clobbering them.
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm/include/asm/processor.h

@@ -97,9 +97,7 @@ static inline void prefetch(const void *ptr)
 {
 	__asm__ __volatile__(
 		"pld\t%a0"
-		:
-		: "p" (ptr)
-		: "cc");
+		:: "p" (ptr));
 }
 
 #define ARCH_HAS_PREFETCHW