Most of the boards use the mmc1 pins and their attributes defined in
mmc1_pins_a. Let's default to that by moving the pinctrl attributes to
the dtsi file. This makes it easier to modify device trees in the
future as there is only one place to change the pinctrl attributes.
Signed-off-by: Joonas Kylmälä <joonas.kylmala@iki.fi>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>