libmsc/sdp: cosmetic: fix less-than-zero comparison of an unsigned value

Change-Id: I57ed17d8457ada69a3c22233f30339d2c0f65bce
Fixes: CID#206075
diff --git a/src/libmsc/sdp_msg.c b/src/libmsc/sdp_msg.c
index 7880978..cc54249 100644
--- a/src/libmsc/sdp_msg.c
+++ b/src/libmsc/sdp_msg.c
@@ -321,7 +321,7 @@
 	if (sscanf(src, "audio %u RTP/AVP", &port) < 1)
 		return -ENOTSUP;
 
-	if (port < 0 || port > 0xffff)
+	if (port > 0xffff)
 		return -EINVAL;
 
 	sdp->rtp.port = port;