net: orinoco: add error handling for failed kmalloc().

With flag 'GFP_ATOMIC', probability of allocation failure is more.
Add error handling after kmalloc() call to avoid null dereference.

Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/orinoco/main.c b/drivers/net/wireless/orinoco/main.c
index dd6c64a..88e3ad2 100644
--- a/drivers/net/wireless/orinoco/main.c
+++ b/drivers/net/wireless/orinoco/main.c
@@ -1336,6 +1336,10 @@
 	unsigned long flags;
 
 	sd = kmalloc(sizeof(*sd), GFP_ATOMIC);
+	if (!sd) {
+		printk(KERN_ERR "%s: failed to alloc memory\n", __func__);
+		return;
+	}
 	sd->buf = buf;
 	sd->len = len;
 	sd->type = type;
@@ -1353,6 +1357,10 @@
 	unsigned long flags;
 
 	sd = kmalloc(sizeof(*sd), GFP_ATOMIC);
+	if (!sd) {
+		printk(KERN_ERR "%s: failed to alloc memory\n", __func__);
+		return;
+	}
 	sd->len = -1; /* Abort */
 
 	spin_lock_irqsave(&priv->scan_lock, flags);