drm/i915: Drop redundant has_hdmi_sink check

intel_hdmi_bpc_possible() will check has_hdmi_sink for us, so no
need to check it in intel_hdmi_mode_clock_valid() anymore.

Cc: Werner Sembach <wse@tuxedocomputers.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210511160532.21446-7-ville.syrjala@linux.intel.com


Reviewed-by: José Roberto de Souza <jose.souza@intel.com>