ARM: dts: cm-t335: add support for MMC

Add pinmux configuration for MMC0 pins.
Add fixed regulator 'vmmc_fixed'.
Enable MMC0 in 4-bit mode.

Signed-off-by: Ilya Ledvich <ilya@compulab.co.il>
Signed-off-by: Uri Mashiach <uri.mashiach@compulab.co.il>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Tony Lindgren <tony@atomide.com>