Merge tag 'u-boot-atmel-2019.10-a' of https://gitlab.denx.de/u-boot/custodians/u-boot-atmel

First set of u-boot-atmel features and fixes for 2019.10 cycle

This includes the Atmel QSPI driver and support for the at91 boards.
This is the port of the driver from Linux, mostly done by Tudor Ambarus.