drm/vmwgfx: Use 2.19 version number to recognize mks-stats ioctls

To let the userspace recognize that it's running on top of a vmwgfx
that supports mks-stat ioctls we need to bump the version number.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Reviewed-by: Neha Bhende <bhenden@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210723165153.113198-4-zackr@vmware.com