glsl: fix return value for subgroupBallot()

The original code attempted to create a second instance of the intrinsic
with only a different return value which isn't possible since the params
(in this case 0 params) are the same. To fix this were need to create
two differently named intrinsics.

Reviewed-by: Qiang Yu <yuq825@gmail.com>

Fixes: a496d84ac88e ("glsl: add KHR_shader_subgroup_ballot builtin functions")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/12510
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33231>
1 file changed