Both VSC8574 and VSC8584 Ethernet PHYs require a firmware patch to be
applied before making use of them.

This adds the firmware for each of them.

The Linux driver using the firmwares is already in Torvalds' tree:
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a5afc1678044a3eea48f0295ae7bc2b13d59b128
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=00d70d8e0e7811ed8acba24e04b9f193c3b84beb



Cc: Allan Nielsen <allan.nielsen@microchip.com>
Cc: Steen Hegelund <steen.hegelund@microchip.com>
Signed-off-by: Quentin Schulz <quentin.schulz@bootlin.com>