isl_output.c: print_affine: drop isl_basic_map argument
The isl_basic_map argument is only used to determine the size
of the affine expression, but ever since
isl-0.15-265-g93ce389e43
(isl_printer_print_map: print explicit representations of divs
in constraints, Tue Dec 1 15:14:21 2015 +0100), the function is
passed both space information and information about local variables.
The size of the affine expression can be determined from these
two pieces of information.
Signed-off-by: Sven Verdoolaege <sven.verdoolaege@gmail.com>