wifi: rtw89: mac: add flags to check if CMAC and DMAC are enabled

Before accessing CMAC and DMAC registers, we should ensure they have been
powered on, so add flag to determine the state. For old chips, we read
registers and check corresponding bit, but it takes extra cost to read.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20231211083341.118047-4-pkshih@realtek.com