arch/sparc: doesn't have atomics

Cores older than v9 don't seem to have atomics so remove it.
Fixes a test build of pulseaudio for example.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

arch/Config.in.sparc

@@ -17,9 +17,6 @@ config BR2_ARCH
 config BR2_ENDIAN
 	default "BIG"
 
-config BR2_ARCH_HAS_ATOMICS
-	default y
-
 config BR2_GCC_TARGET_CPU
 	default "leon3"		if BR2_sparc_leon3
 	default "v8"		if BR2_sparc_v8