Merge tag 'u-boot-stm32-20200424' of https://gitlab.denx.de/u-boot/custodians/u-boot-stm

- Solve stm32mp15 pinctrl dts issue (patch conflict in branches master and next)
- Split device tree for DHCOR Som and AV 96 board
- Update PLL4 setting in AV96 board
- Enable bootd, iminfo, imxtract on DHCOM