ath9k: fix assumptions for idle calls on suspend/resume

ath9k: fix assumptions for idle calls on suspend/resume

mac80211 will notify drivers when to go idle and ath9k
assumed that it would get further notifications for idle
states after a device stop() config call but as per agreed
semantics the idle state of the radio is left up to driver
after mac80211 issues the stop() callback. The driver is
resposnbile for ensuring the device remains idle after
that even between suspend / resume calls.

This fixes suspend/resume when you issue suspend and resume
twice on ath9k when ath9k_stop() was already called. We need
to put the radio to full sleep in order for resume to work
correctly.

What might seem fishy is we are turning the radio off
after resume. The reason why we do this is because we know
we should not have anything enabled after a mac80211 tells
us to stop(), if we resume and never get a start() we won't
get another stop() by mac80211 so to be safe always bring
the 802.11 device with the radio disabled after resume,
this ensures that if we suspend we already have the radio
disabled and only a start() will ever trigger it on.

Cc: stable@kernel.org
Cc: Paul Stewart <pstew@google.com>
Cc: Amod Bodas <amod.bodas@atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>