drm/i915/sdvo: s/sdvo_inputs_mask/sdvo_num_inputs/

The SDVO inputs are reported a simple number, not a bitmask.
Adjust the code to match reality.

Note that we don't actually support dual input SDVO devices,
and we just always use the first input.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230705202122.17915-4-ville.syrjala@linux.intel.com


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