QS: RSSITile: Finally fix the data indicator

The X for data off now changes based on the mobile data enabled setting.
If mobile data is enabled, the rssi tile behaves like stock.
If mobile data is disabled, the X shows to indicate that the user disabled data.

PS1: Inital commit
PS2: Nothin to see here...
PS3: Remove uneccesary wifi check.
     The overlay should be nulled any time the other conditions aren't met
PS4: Remove unused import

Change-Id: I76e63c606f2651a8463f9cd0b3665543b420d72c
Signed-off-by: Evan Anderson <evan1124@gmail.com>