drm/msm: Add support for pointer params

The 64b value field is already suffient to hold a pointer instead of
immediate, but we also need a length field.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20220317165144.222101-2-robdclark@gmail.com


Signed-off-by: Rob Clark <robdclark@chromium.org>