OMAP GPIO driver allowed to be built as loadable module, but it
doesn't set owner field in GPIO chip structure. As result,
module_get/put() API is not working and it's possible to unload
OMAP driver while in use:

  omap_gpio 48051000.gpio: REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED

Hence, add missing configuration.

Cc: Tony Lindgren <tony@atomide.com>
Fixes: cac089f9 ('gpio: omap: Allow building as a loadable module')
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>