drm/i915: Drop some no longer required mode/adjusted_mode parameters

We can get at this easily through intel_crtc->config now.

v2: Drop more stuff gcc spotted.

v3: Drop even more stuff gcc spotted.

v4: Yet more ...

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>