basop32.[ch]: API for div_s() and div_l() different from ITU-STL

For the BASOP functions div_s() and div_l(), apparently the API was changed inside the IVAS code (for both, with and without BASOP_NOGLOB enabled). They are no longer interchangeable with the STL BASOP implementation.

IVAS function declaration:

ivas_error div_s( Word16 *result, Word16 var1, Word16 var2 ); 
ivas_error div_l( Word16 *result, Word32, Word16 ); 

STL function declaration:

Word16 div_s (Word16 var1, Word16 var2);
Word16 div_l (Word32, Word16);

The difference is basically that the IVAS versions return an error-code whereas the STL version just returns a result.

I would propose to revert these changes at least for BASOP_NOGLOB disabled.