decon: mdnie: Store sensorRGB values in main table

The fb notifier callback will call mdnie_update() on
FB_BLANK_UNBLANK, which will then call mdnie_update_sequence()
with the table returned by mdnie_find_table(mdnie).

This will discard the values written to sensorRGB if we do not
save them.

Change-Id: I29cae3f98f64885abd3ebabc43ad13a959a3fffa