ax25: use GFP_KERNEL in ax25_dev_device_up()

ax25_dev_device_up() is only called during device setup, which is
done in user context. In addition, ax25_dev_device_up()
unconditionally calls ax25_register_dev_sysctl(), which already
allocates with GFP_KERNEL.

Since it is allowed to sleep in this function, here we change
ax25_dev_device_up() to use GFP_KERNEL to reduce unnecessary
out-of-memory errors.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peter Lafreniere <pjlafren@mtu.edu>
Link: https://lore.kernel.org/r/20220616152333.9812-1-pjlafren@mtu.eduSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/ax25/ax25_dev.c

@@ -52,7 +52,8 @@ void ax25_dev_device_up(struct net_device *dev)
 {
 	ax25_dev *ax25_dev;
 
-	if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_ATOMIC)) == NULL) {
+	ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_KERNEL);
+	if (!ax25_dev) {
 		printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory\n");
 		return;
 	}
@@ -60,7 +61,7 @@ void ax25_dev_device_up(struct net_device *dev)
 	refcount_set(&ax25_dev->refcount, 1);
 	dev->ax25_ptr     = ax25_dev;
 	ax25_dev->dev     = dev;
-	netdev_hold(dev, &ax25_dev->dev_tracker, GFP_ATOMIC);
+	netdev_hold(dev, &ax25_dev->dev_tracker, GFP_KERNEL);
 	ax25_dev->forward = NULL;
 	ax25_dev->device_up = true;