drm/i915: Flag the execlists context object as dirty after every use

drm/i915: Flag the execlists context object as dirty after every use

commit 903ecd0bb970438c3a60c2c33ec9032d6443bf67 upstream.

Everytime we use the logical context with execlists it becomes dirty (as
the hardware will write the new register values afterwards, as well as
the GPU state that will be used). We need to then flag the context as
dirty everytime since after a swap-out/swap-in cycle the dirty flag will
be cleared, and a further swap-out cycle will then loose the most recent
GPU state.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>