drm/amd/display: allow diags to skip initial link training

drm/amd/display: allow diags to skip initial link training

[why]
diag specify what the full config and is only concerned about pass/fail at the end

having inter-op code like verifiying we can actually train at reported link rate
slows down diag test and add complexity we don't need

[how]
add dc_debug option to skip capability link trianing

also  remove hbr in function name as verify is not specific to hbr

Signed-off-by: Tony Cheng <tony.cheng@amd.com>
Reviewed-by: Ken Chalmers <ken.chalmers@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>