Do not queue display off if power key is pressed during fb wakeup

MCE_DISPLAY_OFF requests must be queued only from fully powered up
display states. Otherwise we create a situation where multiple power
key presses done while the display is off or powering up will bounce
back to display off once initial the off->on transition finishes

[mce] Do not queue display off if power key is pressed during fb wakeup
Merge pull request #121 from spiiroin/fix_powekey_handler

Do not queue display off if power key is pressed during fb wakeup