drm/amd/display: clean up some inconsistent indenting

Eliminate the follow smatch warning:
drivers/gpu/drm/amd/display/dc/dml/calcs/dce_calcs.c:3415 bw_calcs() warn: inconsistent indenting

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>