gpio: remove redundant owner assignments of drivers

A platform_driver need not set an owner since it will be populated
by platform_driver_register().
Likewise for mcb_driver (gpio-menz127.c).

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>