nouveau: Fix compiler warnings about silly address checks in ir_print.

in/out/sv are arrays, so &array[i] is a non-null pointer.  Presumably
numSysVals/Inputs/Outputs are only incremented when there's data in the
arrays, anyway.

Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18536>