We'll want basically the same thing for mdp5, so refactor it out so it
can be shared.
Signed-off-by: NRob Clark <robdclark@gmail.com>

Signed-off-by: NRob Clark <robdclark@gmail.com>

This can be shared between mdp4 and mdp5.  Both use the same set of
parameters to describe the format to the hw.
Signed-off-by: NRob Clark <robdclark@gmail.com>

resync to latest envytools db, add mdp5 registers
Signed-off-by: NRob Clark <robdclark@gmail.com>

There are some little bits and pieces that mdp4 and mdp5 can share, so
move things around so that we can have both in a common parent
directory.
Signed-off-by: NRob Clark <robdclark@gmail.com>