drm/udl: Implement page_flip ioctl
drm/udl: Implement page_flip ioctl

This is a very crude page_flip implementation for UDL. There are ways
to make it better (make it asynchronous, make it do actual vsynced
flips...) but that's for another patch.

[airlied: fixup primary change]

Signed-off-by: Stéphane Marchesin <e16f69845633a0cf74affe1e5a677caa6296c937@chromium.org>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

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