pinctrl: rza1: remove unnecessary static inline function

Having static inline oneliner does not benefit too much when it is
only called from another oneliner function. Remove some of the
'onion'. This simplifies also the coming usage of the gpiolib
defines. We can do conversion from chip bits to gpiolib direction
defines as last step in the get_direction callback. Drivers can
use chip specific values in driver internal functions and do
conversion only once.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20191113071045.GA22110@localhost.localdomain
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>