mmc: omap_hsmmc: Convert to pinctrl_select_default_state()

Let's drop the boilerplate code for managing the default pinctrl state and
convert into using the new pinctrl_select_default_state().

Additionally, move away from using pinctrl_pm_select_default_state() as
it's scheduled for removal and use pinctrl_select_default_state() instead.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20191206170821.29711-6-ulf.hansson@linaro.org