drm/i915: Use encoder->devdata more

drm/i915: Use encoder->devdata more

Switch a lot of the intel_bios_foo() stuff to just accept the
devdata (VBT child device info) directly, instead of taking
detours via vbt.ports[].

Also unify the function naming scheme.

v2: Drop the redundant "encoder" from the dp/hdmi specific functions

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230216000425.32216-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>