iwm - Track firmware state better, and improve handling in iwm_newstate().
* This avoids firmware resets in all the cases in iwm_newstate(). Instead
iwm_bring_down_firmware() is called, which tears down all the STA
connection state, according to the sc->sc_firmware_state value.
* Improve the behaviour of the LED blinking a bit, so it only blinks when
there really is a wireless scan going on.
* Print the newstate arg in debug output of iwm_newstate(), to help in
debugging.
This is inspired by the firmware state maintaining change in OpenBSD's iwm, by
stsp@openbsd.org (OpenBSD Git
0ddb056fb7370664b1d4b84392697cb17d1a414a).