[PATCH 0/2] fix vendor prefix for arcxcnn driver and bindings

[Brian Dodge]

These two patches supercede the prior similar three-patch set 
submitted on 6 Mov 2018. Apologies for the confusion.

This patch is to update the arcxcnn backlight driver to use the
proper "arctic" vendor-prefix and document that in the device-
tree bindings.

There is at least one existing device using the old "arc"
vendor-prefix (Samsung Chromebook Plus), so support for that
remains in the driver source.

Unlike the previous patch set which hasn't been applied, there
there is no actual functionality change here.