net: No line break on netdev_WARN* formatting

Remove the unnecessary line break between the netdev name and reg state
to the actual message that should be printed.

For example, this:
[86730.307236] ------------[ cut here ]------------
[86730.313496] netdevice: enp27s0f0
Message from the driver
[...]

Will be replaced with:
[86770.259289] ------------[ cut here ]------------
[86770.265191] netdevice: enp27s0f0: Message from the driver
[...]
Signed-off-by: Gal Pressman <galp@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -4406,11 +4406,11 @@ do {								\
  * file/line information and a backtrace.
  */
 #define netdev_WARN(dev, format, args...)			\
-	WARN(1, "netdevice: %s%s\n" format, netdev_name(dev),	\
+	WARN(1, "netdevice: %s%s: " format, netdev_name(dev),	\
 	     netdev_reg_state(dev), ##args)
 
 #define netdev_WARN_ONCE(dev, format, args...)				\
-	WARN_ONCE(1, "netdevice: %s%s\n" format, netdev_name(dev),	\
+	WARN_ONCE(1, "netdevice: %s%s: " format, netdev_name(dev),	\
 		  netdev_reg_state(dev), ##args)
 
 /* netif printk helpers, similar to netdev_printk */