ARM: uniphier: allow to disable CONFIG_MICRO_SUPPORT_CARD

Without this, build fails if CONFIG_MICRO_SUPPORT_CARD is disabled.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/mach-uniphier/spl.c b/arch/arm/mach-uniphier/spl.c
index f0df9b1..4c3cad3 100644
--- a/arch/arm/mach-uniphier/spl.c
+++ b/arch/arm/mach-uniphier/spl.c
@@ -13,6 +13,10 @@
 {
 };
 
+void __weak sbc_init(void)
+{
+};
+
 void __weak sg_init(void)
 {
 };