mt76x0: remove has_{2,5}ghz fields of mt76x0_eeprom_params

Remove has_2ghz/has_5ghz fields of mt76x0_eeprom_params data
structure and use mt76_dev ones. This is a preliminary patch
to use shared routines for device allocation

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