HiKey: make RTC out of reset mode

Make RTC out of reset mode since it may be used in UEFI.

Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
diff --git a/plat/hisilicon/hikey/hikey_bl1_setup.c b/plat/hisilicon/hikey/hikey_bl1_setup.c
index f59a545..df0ad8e 100644
--- a/plat/hisilicon/hikey/hikey_bl1_setup.c
+++ b/plat/hisilicon/hikey/hikey_bl1_setup.c
@@ -489,6 +489,15 @@
 	reset_mmc1_clk();
 }
 
+static void hikey_rtc_init(void)
+{
+	uint32_t data;
+
+	data = mmio_read_32(AO_SC_PERIPH_CLKEN4);
+	data |= AO_SC_PERIPH_RSTDIS4_RESET_RTC0_N;
+	mmio_write_32(AO_SC_PERIPH_CLKEN4, data);
+}
+
 /*
  * Function which will perform any remaining platform-specific setup that can
  * occur after the MMU and data cache have been enabled.
@@ -505,6 +514,8 @@
 	hikey_pmussi_init();
 	hikey_hi6553_init();
 
+	hikey_rtc_init();
+
 	hikey_mmc_pll_init();
 
 	memset(&params, 0, sizeof(dw_mmc_params_t));