rtw89: ser: configure top ERR IMR for firmware to recover

Turn on ERR IMR, and then firmware can capture interrupts reflecting
errors to recover hardware states.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220408001353.17188-5-pkshih@realtek.com