This patch converts the TPC70 to use driver model and device tree
description in both SPL and u-boot proper.

Notable changes (DM/DTS conversion):

- PINCTRL{_IMX6}
- DM_I2C
- enable 'regulator' and 'pmic' commands
- DM_MMC and BLK (USDHC)
- DM_ETH
- DM WDT (including SYSRESET)
Signed-off-by: NLukasz Majewski <lukma@denx.de>