The i915 driver is now using atomic properties and atomic commit
to handle the legacy set gamma IOCTL. However, if the driver is
configured without atomic (nuclear_pageflip = false), it won't
update the legacy properties for degamma_lut, gamma_lut and ctm
leaving them out of sync with the atomic version of the properties.

Until the driver is full atomic, make sure we update the non-atomic
version of the properties.

v2: Update the comment with a FIXME.  (Daniel)

v3: Update arguments of the gamma_set vfunc (Lionel)

v4: Fixed vfunc prototype (Lionel)

igt-testcase: kms_pipe_color / legacy-gamma-reset-pipeX
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: stable@vger.kernel.org #v4.7
Signed-off-by: Bob Paauwe <bob.j.paauwe@intel.com>
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1468591142-2253-1-git-send-email-lionel.g.landwerlin@intel.com
(cherry picked from commit a8784875)