Merge tag 'u-boot-imx-2019-02-16' of git://git.denx.de/u-boot-imx

u-boot-imx-2019-02-16
---------------------

- vhybrid: add calibration
- gw_ventana: fixes
- Improve documentation for Secure Boot (HABv4)
- Fix Marvell Switch
- MX6 Sabre, switch to DM
- Fixes for NAND