colibri-imx6ull: migrate pinctrl and regulators to dtb/dm

Migrate pinctrl and regulators to device tree resp. driver model:
Ethernet, NAND and UART.
Drop BOARD_EARLY_INIT_F as it is anyway no longer used.
Enable CMD_DM, CMD_MTD, CMD_REGULATOR and DM_REGULATOR_FIXED.
While at it also update copyright period.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Igor Opaniuk <igor.opaniuk@toradex.com>