ARM: 6469/1: perf-events: squash compiler warning

armv7_pmnc_counter_has_overflowed can return uninitialised data
if an invalid counter is specified.

This patch fixes the code to return 0 in this case, which squashes
the compiler warning from GCC 4.5.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/perf_event.c

@@ -1749,7 +1749,7 @@ static inline int armv7_pmnc_has_overflowed(unsigned long pmnc)
 static inline int armv7_pmnc_counter_has_overflowed(unsigned long pmnc,
 					enum armv7_counters counter)
 {
-	int ret;
+	int ret = 0;
 
 	if (counter == ARMV7_CYCLE_COUNTER)
 		ret = pmnc & ARMV7_FLAG_C;