xdotool: needs MMU support

Fixes:
http://autobuild.buildroot.net/results/d750919a0d5cfb624937c72253651a431212e238



Signed-off-by: Erico Nunes <nunes.erico@gmail.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>