m7-common: Edit camera props for device check

The issue:
  Some camera blobs were checking 'ro.product.device'
  but most custom ROMs use m7ul instead of m7. Because
  of this, ro.product.device was being set to m7ul.
  This created a blue tint on the FFC on m7att
  (and possibly others).

The solution:
  Rather than implement hacky build system workarounds,
  I did a quick edit on the libraries to use ro.haxxxxx.device,
  allowing it to be set independently.