mt76: move mt76x02_eeprom_parse_hw_cap in mt76x02-lib module

Move mt76x02_eeprom_parse_hw_cap utility routine in mt76x02-lib
module in order to be reused in mt76x0 driver

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