xen-netback: Fix pointer incrementation to avoid incorrect logging

xen-netback: Fix pointer incrementation to avoid incorrect logging

[ Upstream commit d8cfbfc4660054150ca1b7c501a8edc0771022f9 ]

Due to this pointer is increased prematurely, the error log contains rubbish.

Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Reported-by: Armin Zentai <armin.zentai@ezit.hu>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: xen-devel@lists.xenproject.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>