w1: w1_therm: make w1_poll_completion static

kernel test robot rightly points out that w1_poll_completion() should be
static, so mark it as such.

Cc: Ivan Zaentsev <[email protected]>
Reported-by: kernel test robot <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: gregkh

drivers/w1/slaves/w1_therm.c

@@ -1031,7 +1031,7 @@ static int reset_select_slave(struct w1_slave *sl)
  *
  * Return: 0 - OK, negative error - timeout
  */
-int w1_poll_completion(struct w1_master *dev_master, int tout_ms)
+static int w1_poll_completion(struct w1_master *dev_master, int tout_ms)
 {
 	int i;