softpipe throws integer division by zero exceptions on windows
when using % with integers in a geometry shader.

v2: Made error results consistent with existing div/mod zero handling in
    tgsi. 64 bit signed integer division by zero returns zero like in
    micro_idiv, unsigned returns ~0u like in micro_udiv.
    Modulo operations always set all result bits to one (like in
    micro_umod).

Reviewed-by: Roland Scheidegger <sroland@vmware.com>