arch/powerpc: always has atomic ops

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Anton Kolesov <Anton.Kolesov@synopsys.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

arch/Config.in.powerpc

@@ -157,6 +157,9 @@ config BR2_ENDIAN
 	default "BIG"    if BR2_powerpc || BR2_powerpc64
 	default "LITTLE" if BR2_powerpc64le
 
+config BR2_ARCH_HAS_ATOMICS
+	default y
+
 config BR2_GCC_TARGET_TUNE
 	default "401"		if BR2_powerpc_401
 	default "403"		if BR2_powerpc_403