ALSA: hda - Fix return value of snd_hda_check_power_state()

The refactoring by commit 9040d102 introduced the new function
snd_hda_check_power_state().  This function is supposed to return true
if the state already reached to the target state, but it actually
returns false for that.  An utterly stupid typo while copy & paste.

Fortunately this didn't influence on much behavior because powering up
AFG usually powers up the child widgets, too.  But the finer power
control must have been broken by this bug.

Cc: <stable@vger.kernel.org> [v3.9+]
Signed-off-by: Takashi Iwai <tiwai@suse.de>