Mainline u-boot spl nvme support

I want to use the mainline u-boot spl to load the u-boot proper(u-boot.itb) from nvme, so that the only part off the nvme is the tpl/spl in the emmc/sd/spi flash.

But now the mainline u-boot has no pcie driver and no nvme support in spl.

I have found the radxa guys using their u-boot in spi flash to boot kernel from nvme. But their pcie driver(https://github.com/radxa/u-boot/commit/096f2c16bbfa24c93a4c87e31334d5b5064dfd0a) has a limitation: It can not be used in u-boot spl, or it would not function properly in u-boot proper and fail the boot. 

After some frustrating tryings and compare with the linux driver, I found that the port initialization process was short cutted and causing the reinitialization malfunctioned. After this correction the pcie driver can be used in spl: it can be reinitialized correctly in u-boot proper.

Bring nvme support into spl is just a mimic from the spl_mmc and spl_usb driver.

Another patch for fixing spl_ext as I want the u-boot.itb and kernel in a ext4 partition on nvme but the existing spl_ext can not load the u-boot.itb properly.

With these patches I can boot nanopc-t4 with u-boot.itb and linux kernel in nvme boot partition and only the u-boot tpl/spl in emmc.

Btw, now the vidconsole of the mainline u-boot is working on rk3399, but usb phys are still missing.

pcie.patch rk3399_boot_nvme.patch spl_ext_fix.patch spl_nvme.patch