drm/i915: Don't disable panel for modesetting if pfit hasn't changed
drm/i915: Don't disable panel for modesetting if pfit hasn't changed

It seems to be possible to program a new mode without disabling the panel
if the panel fitter setup doesn't change. Add support for that.

Signed-off-by: Matthew Garrett <4cf8d479716eba9bc68e0146d95320fcb138b96b@redhat.com>
Acked-by: Jesse Barnes <bc7add126c2dbb8382bf1c28ac262b9363a32706@virtuousgeek.org>
Signed-off-by: Chris Wilson <711c73f64afdce07b7e38039a96d2224209e9a6c@chris-wilson.co.uk>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs