aux/indices: remove useless lines

Presumably these were added to silence a "variable j not used"
compiler warning, but "j" seems used in the loop counter.
Reported by static analysis.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35877>

src/gallium/auxiliary/indices/u_indices_gen.py

@@ -176,7 +176,6 @@ def preamble(f: 'T.TextIO', intype, outtype, inpv, outpv, pr, prim, out_prim):
         f.write('  const ' + intype + '_t* restrict in = (const ' + intype + '_t* restrict)_in;\n')
     f.write('  ' + outtype + '_t * restrict out = (' + outtype + '_t* restrict)_out;\n')
     f.write('  unsigned i, j;\n')
-    f.write('  (void)j;\n')
 
 def postamble(f: 'T.TextIO'):
     f.write('}\n')

src/gallium/auxiliary/indices/u_unfilled_gen.py

@@ -124,7 +124,6 @@ def preamble(f: 'T.TextIO', intype, outtype, prim):
         f.write('  const ' + intype + '_t *in = (const ' + intype + '_t*)_in;\n')
     f.write('  ' + outtype + '_t *out = (' + outtype + '_t*)_out;\n')
     f.write('  unsigned i, j;\n')
-    f.write('  (void)j;\n')
 
 def postamble(f: 'T.TextIO'):
     f.write('}\n')