uml: make three functions static

Make the following three functions static, since they don't need to be global.

arch/um/drivers/mcast_kern.c::mcast_setup()
arch/um/drivers/mconsole_user.c::mconsole_reply_v0()
arch/um/drivers/port_user.c::port_pre_exec()

Acked-by: Jeff Dike <[e-mail]>
Signed-off-by: WANG Cong <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/um/drivers/mcast_kern.c

···
 	.write			= mcast_write,
 };
 
-int mcast_setup(char *str, char **mac_out, void *data)
+static int mcast_setup(char *str, char **mac_out, void *data)
 {
 	struct mcast_init *init = data;
 	char *port_str = NULL, *ttl_str = NULL, *remain;

arch/um/drivers/mconsole_user.c

···
 /* Initialized in mconsole_init, which is an initcall */
 char mconsole_socket_name[256];
 
-int mconsole_reply_v0(struct mc_request *req, char *reply)
+static int mconsole_reply_v0(struct mc_request *req, char *reply)
 {
 	struct iovec iov;
 	struct msghdr msg;

arch/um/drivers/port_user.c

···
 	int pipe_fd;
 };
 
-void port_pre_exec(void *arg)
+static void port_pre_exec(void *arg)
 {
 	struct port_pre_exec_data *data = arg;