[Buildroot] [PATCH] xen: bump to version 4.9.1

[Matthew Weber]

Peter,

On Sun, Jan 14, 2018 at 4:47 PM, Peter Korsgaard <peter at korsgaard.com> wrote:
> Drop 0003-tools-libxc-xc_dom_arm-add-missing-variable-initiali.patch as that
> is now upstream:
>
> https://xenbits.xenproject.org/gitweb/?p=xen.git;a=commit;h=88bfbf90e35f1213f9967a97dee0b2039f9998a4
>
> Drop security patches as 4.9.1 includes up to xsa-245.
>

I ran it through test-pkg and that looked good.

I also did a build against the autobuilder failure below.  Looks like
that failure is still present.
http://autobuild.buildroot.net/results/8bcb80dc93d38bb38ca32ad93d52c22d1176d57e/

Tested-by: Matt Weber <matthew.weber at rockwellcollins.com>