Supported devices are listed in the metadata as the first part of the
DTS compatible. This normally follows the format "vendor,device".

When updating the device name of the 180W 1920-8G PoE an underscore was
used, instead of a comma, to join the vendor and device name. This will
lead to warnings for users wanting to sysupgrade a device with an older
compatible, as the device's info does not match the one the metadata.

Fixes: 987c96e8 ("realtek: rename hpe,1920-8g-poe to match hardware")
Signed-off-by: Sander Vanheule <sander@svanheule.net>