xen/Kconfig: Fix -Wformat-security when compiling with Clang

xen/Kconfig: Fix -Wformat-security when compiling with Clang

Clang observes:

tools/kconfig/conf.c:77:10:
warning: format string is not a string literal (potentially insecure)
      [-Wformat-security]
                printf(_("aborted!\n\n"));
                       ^~~~~~~~~~~~~~~~~

And it is absolutely correct.  gettext() can easily return a string with a %
in.

This could be fixed by switching to using printf("%s", _(...)), or by
switching to puts() (as there is no formatting going on), but the better
option is follow Linux and remove localisation support.

Linux changeset: 694c49a7c01cc87194be40cb26404b58b68c291c
Author: Sam Ravnborg <sam@ravnborg.org>
Date:   Tue May 22 20:36:12 2018

kconfig: drop localization support

The localization support is broken and appears unused.
There is no google hits on the update-po-config target.
And there is no recent (5 years) activity related to the localization.

So lets just drop this as it is no longer used.

Suggested-by: Ulf Magnusson <ulfalizer@gmail.com>
Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
[Ported to Xen]
Reported-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Doug Goldstein <cardoe@cardoe.com>