swscale/utils/sws_setColorspaceDetails(): fix indention

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
swscale/yuv2rgb: clip cy, avoid division by 0 with 0 contrast

Found-by: durandal_1707
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>