glsl: Use signed array index in update_max_array_access()

Avoids a crash in case of negative array index is used in a
shader program.

Cc: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>
1 file changed