[PATCH] gianfar: Fix tests of unsigneds in gfar_parse_group()

[Roel Kluin <roel.kluin@gmail.com>]

interruptTransmit, -Receive and -Error are unsigned so the tests did not work.

This also changes that if irq_of_parse_and_map(np, 0) returns NO_IRQ, that
gfar_parse_group() returns an -EINVAL.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
Found using coccinelle: http://coccinelle.lip6.fr/

diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index 6850dc0..c411682 100644
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -522,6 +522,7 @@ static int gfar_parse_group(struct device_node *np,
 {
 	u32 *queue_mask;
 	u64 addr, size;
+	int irq;
 
 	addr = of_translate_address(np,
 			of_get_address(np, 0, &size, NULL));
@@ -530,20 +531,22 @@ static int gfar_parse_group(struct device_node *np,
 	if (!priv->gfargrp[priv->num_grps].regs)
 		return -ENOMEM;
 
-	priv->gfargrp[priv->num_grps].interruptTransmit =
-			irq_of_parse_and_map(np, 0);
+	irq = irq_of_parse_and_map(np, 0);
+	if (irq < 0)
+		return -EINVAL;
+	priv->gfargrp[priv->num_grps].interruptTransmit = irq;
 
 	/* If we aren't the FEC we have multiple interrupts */
 	if (model && strcasecmp(model, "FEC")) {
-		priv->gfargrp[priv->num_grps].interruptReceive =
-			irq_of_parse_and_map(np, 1);
-		priv->gfargrp[priv->num_grps].interruptError =
-			irq_of_parse_and_map(np,2);
-		if (priv->gfargrp[priv->num_grps].interruptTransmit < 0 ||
-			priv->gfargrp[priv->num_grps].interruptReceive < 0 ||
-			priv->gfargrp[priv->num_grps].interruptError < 0) {
+		irq = irq_of_parse_and_map(np, 1);
+		if (irq < 0)
 			return -EINVAL;
-		}
+		priv->gfargrp[priv->num_grps].interruptReceive = irq;
+
+		irq = irq_of_parse_and_map(np, 2);
+		if (irq < 0)
+			return -EINVAL;
+		priv->gfargrp[priv->num_grps].interruptError = irq;
 	}
 
 	priv->gfargrp[priv->num_grps].grp_id = priv->num_grps;