[FM] "Can't play the track you requested" pops up after tapping "LISTEN"

Select "Start Recording" in options menu -> Wait for SD storage
to be nearly fully occupied -> "Insufficient storage" toast
message displays and "Save recording" dialog pops up ->Tap "Save"
to save the recording -> Tap "LISTEN" to playback the recording,
"Can't play the track you requested" pops up.

The fix is to also check storage free space when handling message
MSG_UPDATE_NOTIFICATION.

bug: 19007352
from: https://partner-android-review.googlesource.com/#/c/193407/



Change-Id: I63d7e22e699cb3ddb90e32a785d5c264258b6a06
Signed-off-by: Benson Huang <benson.huang@mediatek.com>