drm/vmwgfx: Fix Legacy Display Unit atomic drm support

Legacy Display Unit (LDU) fb dirty support used a custom fb dirty callback. Latter
handled only the DIRTYFB IOCTL presentation path but not the ADDFB2/PAGE_FLIP/RMFB
IOCTL path, common for Wayland compositors.

Get rid of the custom callback in favor of drm_atomic_helper_dirtyfb and unify the
handling of the presentation paths inside of vmw_ldu_primary_plane_atomic_update.
This also homogenizes the fb dirty callbacks across all DUs: LDU, SOU and STDU.

Signed-off-by: Martin Krastev <krastevm@vmware.com>
Reviewed-by: Maaz Mombasawala <mombasawalam@vmware.com>
Fixes: 2f5544ff ("drm/vmwgfx: Use atomic helper function for dirty fb IOCTL")
Cc: <stable@vger.kernel.org> # v5.0+
Signed-off-by: Zack Rusin <zackr@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230321020949.335012-3-zack@kde.org