rtw88: fix idle mode flow for hw scan

Upon hw scan completion, idle mode is not re-entered. This might
increase power consumption under no link mode. Fix this by adding the
re-enter flow. We need another work for this since enter_ips waits
for c2h_work to finish, which might lead to deadlock if caller is in
the same work.

Fixes: 10d162b2 ("rtw88: 8822c: add ieee80211_ops::hw_scan")
Signed-off-by: Po-Hao Huang <phhuang@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/20220121070813.9656-3-pkshih@realtek.com