nvc0/ir: use the combined tid special register

nvc0/ir: use the combined tid special register

total instructions in shared programs : 5804448 -> 5804690 (0.00%)
total gprs used in shared programs    : 670065 -> 670065 (0.00%)
total shared used in shared programs  : 548832 -> 548832 (0.00%)
total local used in shared programs   : 21068 -> 21068 (0.00%)

                local     shared        gpr       inst      bytes
    helped           0           0           0           5           5
      hurt           0           0           0         191         191

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>