[SPARC, XEN, NET/CXGB3] use irq_handler_t where appropriate

Rather than hand-rolling our own prototype, make the code more
future-proof by using the standard irq_handler_t typedef.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index 994b5d6..c15e43a 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -2431,7 +2431,7 @@
  *	(MSI-X, MSI, or legacy) and whether NAPI will be used to service the
  *	response queues.
  */
-intr_handler_t t3_intr_handler(struct adapter *adap, int polling)
+irq_handler_t t3_intr_handler(struct adapter *adap, int polling)
 {
 	if (adap->flags & USING_MSIX)
 		return polling ? t3_sge_intr_msix_napi : t3_sge_intr_msix;