The yuv->rgb tables are too small for cliping to be avoidable,

The yuv->rgb tables are too small for cliping to be avoidable,
thus revert the respective optimization. The table generator code
has to be rewritten anyway one day by some volunteer because its
not LGPL, fixing the GPL table generator thus seems like wasted time.

Originally committed as revision 27591 to svn://svn.mplayerhq.hu/mplayer/trunk/libswscale