Fix ubsan complaint about incorrect left-shift in generate_local_port()

The value of "n" used to calculate get the unique port within application
is 10 bit.
This change applies corresponding mask to n, prior to left-shifting it.

lib/socket.c

@@ -129,7 +129,7 @@ static uint32_t generate_local_port(void)
 			nl_write_unlock(&port_map_lock);
 
 			/* ensure we don't return zero. */
-			pid = pid + (n << 22);
+			pid = pid + ((n&0x3ff) << 22);
 			return pid ? pid : 1024;
 		}
 	}