wcn36xx: Do not flush indication queue on suspend/resume

Testing on Android reveals that the flush on both suspend and resume of the
firmware indication work-queue can stall indefinitely.

Given this code path doesn't appear to have been exercised up until now,
removing this flush to unblock this situation.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Benjamin Li <benl@squareup.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210605011140.2004643-5-bryan.odonoghue@linaro.org