drm/i915/mst: change where lane_count and port_clock are set

Semantically mst_stream_find_vcpi_slots_for_bpp() does not seem like the
place to make decisions about lane_count and port_clock. Move them to
the callers, and remove the limits parameter that becomes unused.

This leads to slight duplication, but a) this makes further refactoring
easier, and b) also the SST code sets link parameters in different
places for uncompressed and compressed paths.

Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/101ce3fc6afff55d966336f3ab72090317750f82.1738161945.git.jani.nikula@intel.com


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