mt76: mt7915: add default calibrated data support

Load the default eeprom data when the content of flash/efuse is invalid.
This could help to eliminate some issues due to incorrect or
insufficient rf values.

Co-developed-by: Bo Jiao <Bo.Jiao@mediatek.com>
Signed-off-by: Bo Jiao <Bo.Jiao@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Reviewed-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>