fix(versal): add external declaration

This corrects the MISRA violation C2012-8.4:
A compatible declaration shall be visible when an object or
function with external linkage is defined.

Change-Id: I91817596c5de84b259a5dffcc01a7b1106a5b7a4
Signed-off-by: Maheedhar Bollapalli <maheedharsai.bollapalli@amd.com>
diff --git a/plat/xilinx/versal/sip_svc_setup.c b/plat/xilinx/versal/sip_svc_setup.c
index d449f74..3027946 100644
--- a/plat/xilinx/versal/sip_svc_setup.c
+++ b/plat/xilinx/versal/sip_svc_setup.c
@@ -68,14 +68,14 @@
  *
  * Return: Unused.
  */
-uintptr_t sip_svc_smc_handler(uint32_t smc_fid,
-			     u_register_t x1,
-			     u_register_t x2,
-			     u_register_t x3,
-			     u_register_t x4,
-			     void *cookie,
-			     void *handle,
-			     u_register_t flags)
+static uintptr_t sip_svc_smc_handler(uint32_t smc_fid,
+				u_register_t x1,
+				u_register_t x2,
+				u_register_t x3,
+				u_register_t x4,
+				void *cookie,
+				void *handle,
+				u_register_t flags)
 {
 	VERBOSE("SMCID: 0x%08x, x1: 0x%016" PRIx64 ", x2: 0x%016" PRIx64 ", x3: 0x%016" PRIx64 ", x4: 0x%016" PRIx64 "\n",
 		smc_fid, x1, x2, x3, x4);