drm/i915/selftests: Fix kbuild error

drm/i915/selftests: Fix kbuild error

After applying af2788925ae0 ("drm/i915: Squelch reset messages during
selftests") out of sequence, I missed fixing up a call to i915_reset().

Reported-by: kbuild test robot <kbuild-all@01.org>
Fixes: af2788925ae0 ("drm/i915: Squelch reset messages during selftests")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20170725125336.11969-1-chris@chris-wilson.co.uk
Reviewed-by: David Weinehall <david.weinehall@linux.intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>