tg3: Fix irq alloc error cleanup path

This patch fixes a bug where the irq error cleanup path did not free all
the resources it allocated.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Ben Li <benli@broadcom.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>