drm/i915/hdmi: stop caching has_hdmi_sink in struct intel_hdmi

Use the information stored in display info.

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/5cdb4731260b062c0f0ad2f8b64195c9a57bcb76.1685437500.git.jani.nikula@intel.com