There's a new register pair for 128b/132b mode where you need to set the
pixel clock in Hz.

v2: Fix UHBR rate check, use intel_dp_is_uhbr() helper

Bspec: 54128
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/a2902cc188973f022f282f2a77e693afdecefb5a.1631191763.git.jani.nikula@intel.com