NVMe support on RPi CM4 board

[Luis Alfredo da Silva]

I compiled u-boot version 2023-07 and boot it on a RPi CM4 using a PCIe M.2
NVMe drive, but it doesn't appear to be working.

Once u-boot has started and boot successfully it recognizes the PCIe device
giving me the next output

U-Boot> pci
BusDevFun  VendorId   DeviceId   Device Class       Sub-Class
_____________________________________________________________
00.00.00   0x14e4     0x2711     Bridge device           0x04
01.00.00   0x1c5c     0x174a     Mass storage controller 0x08

but when trying to use the nvme scan and nvme info there is not output.

NVMe drive has two partitions 1st is a FAT partition, and 2nd is a EXT4
partition, the RPi firmware recognizes the FAT partition and u-boot boot
correctly.

I don't know if this worked before, but I saw in the mailing list that
there could be already support for other ARM64 boards.