ARM: socfpga: abolish CONFIG_SOCFPGA

Replace CONFIG_SOCFPGA with CONFIG_ARCH_SOCFPGA.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 15d60b9..6a01759 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -49,7 +49,7 @@
 	zynq-zc770-xm013.dtb
 dtb-$(CONFIG_AM33XX) += am335x-boneblack.dtb
 
-dtb-$(CONFIG_SOCFPGA) +=				\
+dtb-$(CONFIG_ARCH_SOCFPGA) +=				\
 	socfpga_arria5_socdk.dtb			\
 	socfpga_cyclone5_socdk.dtb			\
 	socfpga_cyclone5_socrates.dtb