memstick: Remove useless else branch

Remove else branch on line 334 of memstick.c, after the return of the
previous branch. Found by checkpatch.

Signed-off-by: Joey Pabalan <jpabalanb@gmail.com>
Link: https://lore.kernel.org/r/20210313173740.GA580681@joeylaptop
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>