mt76x0: pci: report firmware version using ethtool

Report via ethtool fw_ver and build_ver members of mt76x02_fw_header
data structure similarly to what is reported in the syslog

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>