mmc: mvsdio: don't use devm_pinctrl_get_select_default() in probe

Since commit ab78029e (drivers/pinctrl: grab default handles from device
core), we can rely on device core for setting the default pins.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>