Merge tag 'u-boot-atmel-2021.07-a' of https://source.denx.de/u-boot/custodians/u-boot-atmel into next

First set of u-boot-atmel features for 2021.07 cycle:
This small feature set includes the implementation of the slew rate for
the PIO4 pin controller device, and a fix for arm926ejs-based
microprocessors that avoids a crash.