tools: drop obsolete xen-ringwatch

tools: drop obsolete xen-ringwatch

This utility can't possibly work with modern Xen setup: none of the
sysfs path used (under /sys/devices/xen-backend) is documented as
stable ABI in upstream Linux kernel.

Archaeology shows that the path used could have been part of the
xenolinux fork which never got upstreamed.

Its utility is zero nowadays. Drop it.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>