ath11k: add WMI calls required for handling BSS color

If the he_operation field of the beacon sets a BSS color, we need to inform
the FW of the settings. This patch adds the WMI command handlers required
to do so.

Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>