ARM: uniphier: add DRAM init code for ProXstream2/PH1-LD6b

As mentioned in the log of commit 019df879a93e2 (ARM: uniphier: add
ProXstream2 and PH1-LD6b support), the DRAM init code was missing
for a long time.  Finally, here it is.  SPL works now.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/mach-uniphier/init/init-proxstream2.c b/arch/arm/mach-uniphier/init/init-proxstream2.c
index 859e2e9..029c544 100644
--- a/arch/arm/mach-uniphier/init/init-proxstream2.c
+++ b/arch/arm/mach-uniphier/init/init-proxstream2.c
@@ -12,6 +12,8 @@
 
 int proxstream2_init(const struct uniphier_board_data *bd)
 {
+	int ret;
+
 	proxstream2_sbc_init(bd);
 
 	support_card_reset();
@@ -37,5 +39,11 @@
 
 	led_puts("L4");
 
+	ret = proxstream2_umc_init(bd);
+	if (ret)
+		return ret;
+
+	led_puts("L5");
+
 	return 0;
 }