Merge tag 'rockchip-for-v2019.07-rc5' of https://gitlab.denx.de/u-boot/custodians/u-boot-rockchip

- new board: rk3328 rock64
- rk3328 SPL support
- rk3399 spl/tpl board init cleanup
- use environment to get ATF binary for rk3399
- build u-boot.itb target by default for rockchip
- rk3399 board init fix after pinctrl patch set merged