util-linux: add support for Xtensa

[Thomas Petazzoni: rename patch to not have the package version in the
patch file name, adjust the commit title.]

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>