CHROMIUM: drm: Fix a memory leak in drm_crtc_check_state().

Modify drm_crtc_check_state() to always clean up the allocated
struct drm_display_mode.

BUG=chrome-os-partner:34339, chrome-os-partner:34031, chrome-os-partner:34607
TEST=Run on a platform with an active workload for several hours,
TEST=watching top to make sure that free memory does not decrease
TEST=over time.

Change-Id: I6ae5c7bed91540127c4124edc7b263c063ae59df
Signed-off-by: Jim Bride <jim.bride@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/236321
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-by: James Ausmus <james.ausmus@intel.com>
Tested-by: James Ausmus <james.ausmus@intel.com>
(cherry picked from commit 2b25f7419e464a77e07d6ceac4488de79e2cb61e)
Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/236614
Reviewed-by: David Sodman <dsodman@chromium.org>
Merge branch 'chromeos-3.8' of https://chromium.googlesource.com/chromiumos/third_party/kernel into chromeos-3.8