Use correct type when reading SCR register

The Secure Configuration Register is 64-bits in AArch64 and 32-bits in
AArch32. Use u_register_t instead of unsigned int to reflect this.

Change-Id: I51b69467baba36bf0cfaec2595dc8837b1566934
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
diff --git a/plat/rockchip/common/plat_pm.c b/plat/rockchip/common/plat_pm.c
index c9563c9..6926887 100644
--- a/plat/rockchip/common/plat_pm.c
+++ b/plat/rockchip/common/plat_pm.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -182,7 +182,7 @@
  ******************************************************************************/
 void rockchip_cpu_standby(plat_local_state_t cpu_state)
 {
-	unsigned int scr;
+	u_register_t scr;
 
 	assert(cpu_state == PLAT_MAX_RET_STATE);