gpio: omap: move omap_gpio_request() and omap_gpio_free()

Move these two functions to live beside the rest of the gpio chip
implementation, rather than in the middle of the irq chip
implementation.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>