drm/amd/display: clean up some inconsistent indenting

Eliminate the follow smatch warning:
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c:2246
dp_perform_8b_10b_link_training() warn: inconsistent indenting
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Reported-by: NAbaci Robot <abaci@linux.alibaba.com>
Signed-off-by: NYang Li <yang.lee@linux.alibaba.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>