ARM: UniPhier: remove unnecessary CONFIG_SYS_SOC

Since commit a86ac9540e (ARM: UniPhier: include <mach/*.h> instead
of <asm/arch/*.h>), UniPhier platform does not need the symbolic
link arch/arm/include/asm.  This option is not necessary either.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/arm/mach-uniphier/Kconfig

@@ -1,9 +1,6 @@
 menu "Panasonic UniPhier platform"
 	depends on ARCH_UNIPHIER
 
-config SYS_SOC
-	default "uniphier"
-
 config SYS_CONFIG_NAME
 	default "uniphier"