package/xenomai: update udev rules search path
The udev rules has been moved to kernel/cobalt/udev.
Fixes:
http://autobuild.buildroot.net/results/8eb/8eb4643faed523ffccd421f20c2955adfde634a6
Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>