Pull xen fix from Juergen Gross:
"A fix for the Xen pv network drivers (frontend and backend) avoiding
the network connection to become unusable due to an illegal MTU"
* tag 'for-linus-4.14c-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen-netfront, xen-netback: Use correct minimum MTU values