wifi: rtlwifi: Add new members to struct rtl_priv for RTL8192DU

These are needed for the dual MAC version of RTL8192DU.

The two mutexes are used to avoid concurrent access to the hardware
from the two USB interfaces.

The two arrays are filled by one interface during LC calibration and
accessed by the other interface during channel switching.

Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://msgid.link/d1bf581b-de41-4d09-bf56-768c2fc29dd3@gmail.com