<sys/io.h> on ARM hasn't worked for a long, long time, so it was removed
it from glibc upstream.
Remove the include to avoid a compilation failure on ARM with glibc.
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Closes: https://gitlab.freedesktop.org/xorg/xserver/issues/840
(cherry picked from commit fe4cd0e7f5)