U-Boot with direct NVMe boot support for eMMC/SPI Flash

[belfastraven]

Thanks for this @pcm720 .  Although I did sucessfully build from your git using  the current u-boot (on ubuntu focal desktop),  I just grabbed your released spiflash.bin and flashed in on current (from unstable) Manjaro.    It's great--boots even faster than it did with the Feb. mainline uboot and atf.  So far I've only booted from my NVME but will test other devices, too.  

A note for other newbies:  Flash_erase is part of the mtd-utils package in arch/Manjaro and one needs to sudo the flash_erase and dd commands if not logged in as root.  

thanks again.