pinctrl: simplify the re-enable old state code in pinctrl_select_state

Instead of just enabling the settings that were disabled in the 1st
loop, it's simpler to recall pinctrl_select_state with the old state.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>