mt76: connac: introduce mt76_sta_cmd_info data structure

Introduce mt76_sta_cmd_info data structure to contain parameters passed
to mt76_sta_cmd_info routine. This is preliminary patch to properly
configure rcpi for mt7921 devices.

Tested-by: Jayden.Kuo <jayden.kuo@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>