drm/i915/dvo: s/dev_priv/i915/

Follow the modern style and rename most 'dev_priv' variables
to 'i915'.

intel_dvo_init_dev() is the sole exception since it needs the
magic 'dev_priv' variable for the DPLL register macros.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221118105525.27254-9-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>