drm/dsi: Add DSI transfer helper
drm/dsi: Add DSI transfer helper

A common pattern is starting to emerge for higher level transfer
helpers. Create a new helper that encapsulates this pattern and avoids
code duplication.

Acked-by: Andrzej Hajda <dcc2b772defa18622a340d324a717fd6b8ee2807@samsung.com>
Reviewed-by: Sean Paul <f9352ecf3e2294bdb914c99cca8d12601acec118@chromium.org>
Signed-off-by: Thierry Reding <3055038c414aef68bf32c33b8118623e7554e0f2@nvidia.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs