Merge tag 'for-master-20181130' of git://git.denx.de/u-boot-rockchip

Improvements:
- RK3188 USB-UART functionality
- errors triggering a hard-stop in SPL on the RK3399 are reported
- Rockchip RV1108 (SoC) support
- MicroCrystal RV3029 (RTC) DM driver

Fixes:
- RK3188 early UART setup
- limit SD-card frequency to 40MHz on the RK3399-Q7
- MIPI fixes
- RK3399 CPUB clock initialisation