mt76: mt7915: introduce bss coloring support

Introduce mcu APIs to configure bss coloring and to report bss coloring
collisions. Add support to report coloring countdown in beacon sent by
the device.

Co-developed-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>