tools: fix make uninstall

tools: fix make uninstall

The uninstall target does not know about the paths it removes because
the toplevel Makefile does not include the required files.

Move the commands to tools/Makefile because all files come from subdirs
in tools/ anyway. Drop the removal of $(XEN_RUN_DIR) because it gets
created at runtime. Drop the removal of systemd related files because
the wildcard matches everything.

The proper fix is to remove the files and directories in the Makefiles
which install them. But this version is the least intrusive change at
this point.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>