wifi: rtw89: 8852c: declare to support two chanctx

We are going to allow RTL8852C to support MCC (multi-channel concurrency).
So, we increase 8852c::support_chanctx_num up to 2.

Signed-off-by: Zong-Zhe Yang <kevin_yang@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/20230921003559.11588-4-pkshih@realtek.com