ARM: dts: ux500: Add alternative SDI pin configs

ARM: dts: ux500: Add alternative SDI pin configs

SDI0/SDI1 can be used in configurations where some of the pins
(e.g. direction control) are not used. The pinctrl driver has
separate pin groups for them.

Add new pin configurations for:
  - mc0_a_2: like mc0_a_1, but without CMDDIR/DAT0DIR/DAT2DIR
  - mc1_a_2: like mc1_a_1, but without FBCLK

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20191125122256.53482-3-stephan@gerhold.net
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>