fix(xilinx): resolve misra rule 12.2 violations

Fixed below MISRA violation:
- MISRA Violation: MISRA-C:2012 R.12.2:
  - The right hand operand of a shift operator shall lie in the range
    zero to one less than the width in bits of the essential type of
    the left hand operand.
- Fix:
  - Type casted left operand to a larger width than shift.

Change-Id: I662ff57e52d1260e2f1a0de595f19a9143714892
Signed-off-by: Devanshi Chauhan Alpeshbhai <devanshi.chauhanalpeshbhai@amd.com>
diff --git a/plat/xilinx/common/include/pm_api_sys.h b/plat/xilinx/common/include/pm_api_sys.h
index 793b270..fc55cc3 100644
--- a/plat/xilinx/common/include/pm_api_sys.h
+++ b/plat/xilinx/common/include/pm_api_sys.h
@@ -60,7 +60,8 @@
  * Assigning of argument values into array elements.
  */
 #define PM_PACK_PAYLOAD1(pl, mid, flag, arg0) {	\
-	pl[0] = (uint32_t)(((uint32_t)(arg0) & 0xFFU) | ((mid) << 8U) | ((flag) << 24U)); \
+	pl[0] = (uint32_t)(((uint32_t)(arg0) & 0xFFU) | \
+		((uint32_t)(mid) << 8U) | ((uint32_t)(flag) << 24U)); \
 }
 
 #define PM_PACK_PAYLOAD2(pl, mid, flag, arg0, arg1) {		\