leds: as3676_semc: regrant users access to leds' real safe max current

This extends the patch for hardcoded stock values.
With only it the users can't go above stock values, even though the leds are made to work
on bigger currents between 20-25mA.

This commit fixes it and lets users again to reach hardware's max safe current through scripts and also maintains OEMs' stock values if no script is used.

Change-Id: I43834acf6e223cab2eaf93c1e74116a2839270df
Signed-off-by: Konstantinos Missos <ctcaer@gmail.com>