ARM: 6213/1: atomic64_test: add ARM as supported architecture

ARM has support for the atomic64_dec_if_positive operation
so ensure that it is tested by the atomic64_test routine.
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

lib/atomic64_test.c

@@ -114,7 +114,7 @@ static __init int test_atomic64(void)
 	BUG_ON(v.counter != r);
 
 #if defined(CONFIG_X86) || defined(CONFIG_MIPS) || defined(CONFIG_PPC) || \
-    defined(CONFIG_S390) || defined(_ASM_GENERIC_ATOMIC64_H)
+    defined(CONFIG_S390) || defined(_ASM_GENERIC_ATOMIC64_H) || defined(CONFIG_ARM)
 	INIT(onestwos);
 	BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1));
 	r -= one;