wifi: rtw88: Fix AP mode incorrect DTIM behavior

Broadcast and multicast packets in high queue should be transmitted
all at once during DTIM. But without proper settings, hardware fails
to recognize that there are multiple packets and fetches only one.
Fix this by signaling hardware with more data bit set when there are
packets in the high queue.

Signed-off-by: Po-Hao Huang <phhuang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230616125540.36877-3-pkshih@realtek.com