drm/i915: s/mode/adjusted_mode/ in functions that really get passed the adjusted_mode

Rename the function argument to 'adjusted_mode' whenever the function
only ever gets passed the adjusted_mode.

v2: Update due to intel_dsi.c changes

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>