wifi: rtw89: coex: Not to enable firmware report when WiFi is power saving

If driver enable firmware report during WiFi power saving, the
firmware timer will lead to some power saving issue like,
fail to enter LPS, can not leave LPS or some unexpected issue.

Signed-off-by: Ching-Te Ku <ku920601@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/20230314020617.28193-3-pkshih@realtek.com