[iwm] Fix several nitpicks in iwm(4).
Move some declarations to if_iwmreg.h. Remove iwm_fw_alive(); just call iwm_post_alive() directly. Simplify iwm_mvm_add_sta(). Return timeout error from iwm_apm_init(). Print a message when init (i.e. boot) firmware fails to load. Remove some commented-out code which wouldn't compile anyway. Move iwm_mvm_tx_fifo to if_iwmreg.h to match better where Linux puts it. Taken-From: OpenBSD (if_iwm.c r1.80 and if_iwmreg.h r1.11)
Submitted by: Imre Vadasz <imre@vdsz.com>
Obtained from: DragonflyBSD 29fcb331e5620ae145a6ab9cdda830e22fff626a