mt76: mt7615: move drv_own/fw_own in mt7615_mcu_ops

Introduce set_drv_ctrl and set_fw_ctrl function pointers in
mt7615_mcu_ops data structure. This is a preliminary patch to enable
runtime-pm for non-pci chipsets

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>