rockchip/rk3399: do secure timer init in pmusram

we will use timer in pmusarm, when logic power rail shutdown,
the secure timer will gone, so need to initial it in pmusram.

Change-Id: I472e7eec3fc197f56223e6fff9167556c1c5e3bc
Signed-off-by: Lin Huang <hl@rock-chips.com>
diff --git a/plat/rockchip/rk3399/drivers/dram/suspend.c b/plat/rockchip/rk3399/drivers/dram/suspend.c
index 7d4abf0..f66150a 100644
--- a/plat/rockchip/rk3399/drivers/dram/suspend.c
+++ b/plat/rockchip/rk3399/drivers/dram/suspend.c
@@ -726,6 +726,8 @@
 	uint32_t channel_mask = 0;
 	uint32_t channel;
 
+	sram_secure_timer_init();
+
 	/*
 	 * we switch ddr clock to abpll when suspend,
 	 * we set back to dpll here