mwl8k: always apply configuration even when device is idle

Fix settings not being applied when the device is idle and the firmware
gets reloaded (because of changing from STA to AP mode). This caused
the device using the wrong channel (and likely band), e.g. a 5 GHz only
card still defaulted to channel 6 in the 2.4 GHz band when left
unconfigured.

This issue was always present, but only made visible with "mwl8k: Do not
call mwl8k_cmd_set_rf_channel unconditionally" (0f4316b9), since before
that the channel was (re-)configured at the next _config call even when
it did not change from the mac80211 perspective.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>