SAM E54 Xplained Pro: add support for SST26VF064B flash chip

[tomiahola]

Fixes #8047

[dhalbert]

Thanks for the update!

build failed

[tannewt]

@tomiahola Please test the build for the board under artifacts here: https://github.com/adafruit/circuitpython/actions/runs/5147018667?pr=8054

[dhalbert]

@tannewt Oddly these work:

ports/atmel-samd/boards/bdmicro_vina_d51_pcb7/mpconfigboard.mk:10:EXTERNAL_FLASH_DEVICES = "MX25L51245G","GD25S512MD"
ports/atmel-samd/boards/bdmicro_vina_d51/mpconfigboard.mk:13:EXTERNAL_FLASH_DEVICES = "MX25L12833F","MX25L51245G","GD25S512MD"
ports/atmel-samd/boards/bdmicro_vina_d21/mpconfigboard.mk:10:EXTERNAL_FLASH_DEVICES = "MX25L51245G","GD25S512MD"

Maybe because there are no spaces.

[tomiahola]

@tannewt, Hi, I downloaded the .uf2 file under the artifacts and installed it into the board:
Now there is no response from the board, neither CIRCUITPY or USB Drive appears, and no COM port is detected.

[dhalbert]

I apologize this before testing; I misunderstood about whether testing had happened. Since it didn't work before, not such big deal, but sounds like the flash chip definition may be wrong. There is no other board that uses this chip (or the smaller 2MB version), so there may be an error in the chip definition in nvm.toml.