fix(zynqmp): resolve the misra 4.6 warnings

MISRA Violation: MISRA-C:2012 R.4.6
- Using basic numerical type int rather than a typedef
that includes size and signedness information.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@xilinx.com>
Change-Id: I9fb686e7aa2b85af6dfcb7bb5f87eddf469fb85c
diff --git a/plat/xilinx/zynqmp/plat_zynqmp.c b/plat/xilinx/zynqmp/plat_zynqmp.c
index 58a52a3..25ebac6 100644
--- a/plat/xilinx/zynqmp/plat_zynqmp.c
+++ b/plat/xilinx/zynqmp/plat_zynqmp.c
@@ -7,7 +7,7 @@
 #include <plat_private.h>
 #include <plat/common/platform.h>
 
-int plat_core_pos_by_mpidr(u_register_t mpidr)
+int32_t plat_core_pos_by_mpidr(u_register_t mpidr)
 {
 	if (mpidr & MPIDR_CLUSTER_MASK) {
 		return -1;