kbuild: use SoC-specific CONFIG to descend into SoC directory

Use "obj-$(CONFIG_FOO) += foo/" where it is possible.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/arch/arm/cpu/arm926ejs/Makefile b/arch/arm/cpu/arm926ejs/Makefile
index bd1ef8b..adcea9f 100644
--- a/arch/arm/cpu/arm926ejs/Makefile
+++ b/arch/arm/cpu/arm926ejs/Makefile
@@ -14,4 +14,17 @@
 endif
 endif
 
-obj-y += $(if $(SOC),$(SOC)/)
+obj-$(CONFIG_ARMADA100) += armada100/
+obj-$(CONFIG_AT91FAMILY) += at91/
+obj-$(CONFIG_ARCH_DAVINCI) += davinci/
+obj-$(CONFIG_KIRKWOOD) += kirkwood/
+obj-$(if $(filter lpc32xx,$(SOC)),y) += lpc32xx/
+obj-$(CONFIG_MB86R0x) += mb86r0x/
+obj-$(CONFIG_MX25) += mx25/
+obj-$(CONFIG_MX27) += mx27/
+obj-$(if $(filter mxs,$(SOC)),y) += mxs/
+obj-$(CONFIG_ARCH_NOMADIK) += nomadik/
+obj-$(CONFIG_ORION5X) += orion5x/
+obj-$(CONFIG_PANTHEON) += pantheon/
+obj-$(if $(filter spear,$(SOC)),y) += spear/
+obj-$(CONFIG_ARCH_VERSATILE) += versatile/