arch/arm: remove setting gcc's apcs-gnu ABI (aka OABI)

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

arch/Config.in.arm

@@ -142,5 +142,4 @@ config BR2_GCC_TARGET_ARCH
 	default "iwmmxt"	if BR2_iwmmxt
 
 config BR2_GCC_TARGET_ABI
-	default "apcs-gnu"	if BR2_ARM_OABI
-	default "aapcs-linux"	if BR2_ARM_EABI
+	default "aapcs-linux"