drm/i915/dp: Fix the computation for compressed_bpp for DISPLAY < 13

drm/i915/dp: Fix the computation for compressed_bpp for DISPLAY < 13

For DISPLAY < 13, compressed bpp is chosen from a list of
supported compressed bpps. Fix the condition to choose the
appropriate compressed bpp from the list.

Fixes: 1c56e9a39833 ("drm/i915/dp: Get optimal link config to have best compressed bpp")
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: <stable@vger.kernel.org> # v6.7+
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10162
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240305054443.2489895-1-ankit.k.nautiyal@intel.com