chelsio: sparse warning fixes (old cxgb2)

Fix problems detected by sparse:
1. whole chunk of MAC code was for defined and never used
2. hook for running ext intr in workqueue wasn't being used

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/chelsio/common.h b/drivers/net/chelsio/common.h
index b5de445..846ca53 100644
--- a/drivers/net/chelsio/common.h
+++ b/drivers/net/chelsio/common.h
@@ -372,6 +372,7 @@
 extern void t1_interrupts_disable(adapter_t *adapter);
 extern void t1_interrupts_clear(adapter_t *adapter);
 extern int t1_elmer0_ext_intr_handler(adapter_t *adapter);
+extern void t1_elmer0_ext_intr(adapter_t *adapter);
 extern int t1_slow_intr_handler(adapter_t *adapter);
 
 extern int t1_link_start(struct cphy *phy, struct cmac *mac, struct link_config *lc);