rockchip: rk3399: enable secure accessing for SRAM

Sorry to miss the security configuration for SRAM, if we don't support
it, somebody may modify the comment of SRAM in the non-secure space.
Let's fix this issue.
Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>

plat/rockchip/rk3399/drivers/secure/secure.c

@@ -163,7 +163,7 @@ void secure_sgrf_init(void)
 	mmio_write_32(SGRF_BASE + SGRF_SLV_SECURE_CON0_4(3),
 		      SGRF_SLV_S_WMSK | SGRF_SLV_S_ALL_NS);
 	mmio_write_32(SGRF_BASE + SGRF_SLV_SECURE_CON0_4(4),
-		      SGRF_SLV_S_WMSK | SGRF_SLV_S_ALL_NS);
+		      SGRF_SLV_S_WMSK | SGRF_INTSRAM_S);
 }
 
 void secure_sgrf_ddr_rgn_init(void)

plat/rockchip/rk3399/drivers/secure/secure.h

@@ -62,6 +62,8 @@
 
 #define SGRF_PMUSRAM_S			BIT(8)
 
+#define SGRF_INTSRAM_S			BIT(13)
+
 /* ddr region */
 #define SGRF_DDR_RGN_0_16_WMSK		0x0fff  /* DDR RGN 0~16 size mask */