fix(spmd): coverity scan issues

Coverity defects fixed by this patch are:
*** CID 400208:  Performance inefficiencies  (PASS_BY_VALUE)
/include/services/el3_spmd_logical_sp.h: 108 in
ffa_partition_info_regs_get_last_idx()

*** CID 400207:  Performance inefficiencies  (PASS_BY_VALUE)
/services/std_svc/spmd/spmd_logical_sp.c: 359 in
ffa_partition_info_regs_get_part_info()

Signed-off-by: Raghu Krishnamurthy <raghu.ncstate@gmail.com>
Change-Id: I9597377a8ec3d5519995e1619d99ee7102f33939
diff --git a/plat/arm/board/fvp/fvp_spmd_logical_sp.c b/plat/arm/board/fvp/fvp_spmd_logical_sp.c
index 37b4466..8841fc1 100644
--- a/plat/arm/board/fvp/fvp_spmd_logical_sp.c
+++ b/plat/arm/board/fvp/fvp_spmd_logical_sp.c
@@ -32,7 +32,7 @@
 		panic();
 	}
 
-	num_partitions = ffa_partition_info_regs_get_last_idx(ret) + 1;
+	num_partitions = ffa_partition_info_regs_get_last_idx(&ret) + 1;
 	if (num_partitions > SPMD_LP_MAX_SUPPORTED_SP) {
 		panic();
 	}
@@ -41,7 +41,7 @@
 
 	for (uint16_t i = 0; i < num_partitions; i++) {
 		INFO("***Start Partition***\n");
-		if (!ffa_partition_info_regs_get_part_info(ret, i, &part_info[i]))
+		if (!ffa_partition_info_regs_get_part_info(&ret, i, &part_info[i]))
 			panic();
 		INFO("\tPartition ID: 0x%x\n", part_info[i].ep_id);
 		INFO("\tvCPU count:0x%x\n", part_info[i].execution_ctx_count);