be2net: fix spurious interrupt handling in intx mode

Occasionally we may see an interrupt without an event in the eq.
In intx, we currently see the event queue and return IRQ_NONE causing
a the irq to be disabled ("no one cared".) Instead, read the CEV_ISR
reg to check the existence of the interrupt.

Signed-off-by: Sathya Perla <sathyap@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/benet/be_hw.h b/drivers/net/benet/be_hw.h
index b02e805..29c33c7 100644
--- a/drivers/net/benet/be_hw.h
+++ b/drivers/net/benet/be_hw.h
@@ -55,6 +55,10 @@
 #define MEMBAR_CTRL_INT_CTRL_PFUNC_MASK  	0x7 	/* bits 26 - 28 */
 #define MEMBAR_CTRL_INT_CTRL_PFUNC_SHIFT	26
 
+/********* ISR0 Register offset **********/
+#define CEV_ISR0_OFFSET 			0xC18
+#define CEV_ISR_SIZE				4
+
 /********* Event Q door bell *************/
 #define DB_EQ_OFFSET			DB_CQ_OFFSET
 #define DB_EQ_RING_ID_MASK		0x1FF	/* bits 0 - 8 */