wifi: mt76: mt7996: support more options for mt7996_set_bitrate_mask()

Add support to configure parameters at runtime, such as mcs, gi, and
he_ltf. Note that EHT mode does not support this feature yet.

Co-developed-by: MeiChia Chiu <MeiChia.Chiu@mediatek.com>
Signed-off-by: MeiChia Chiu <MeiChia.Chiu@mediatek.com>
Signed-off-by: Howard Hsu <howard-yh.hsu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>