drm/amd/display: Update LTTPR UHBR link rate support struct

[WHY]
Update field order to match DP2.0 spec SCR

Reviewed-by: George Shen <George.Shen@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Michael Strauss <michael.strauss@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>