drm/i915: Pass dev_priv to intel_setup_outputs()

Pass dev_priv to intel_setup_outputs() and functions called by it, since
those are all intel i915 specific functions. Also, in the majority of
the functions dev_priv is used more often than dev. In the rare cases
where there are a few calls back into drm core, a local dev variable was
added.

v2: Don't convert dev to &dev_priv->drm in intel_dsi_init. (Ville)
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1479910904-11005-1-git-send-email-ander.conselvan.de.oliveira@intel.com