[gdb/syscalls] Sync with strace v6.13

[gdb/syscalls] Sync with strace v6.13

After syncing with strace v6.13 using:
...
$ update-linux-defaults.sh ~/upstream/strace.git
...
we have a few new entries in linux-defaults.xml.in:
...
  <syscall name="getxattrat" groups="descriptor,file"/>
  <syscall name="listxattrat" groups="descriptor,file"/>
  <syscall name="removexattrat" groups="descriptor,file"/>
  <syscall name="setxattrat" groups="descriptor,file"/>
...

Regenerate most *-linux.xml.in files using:
...
$ ./update-linux-from-src.sh ~/upstream/linux-stable.git
...
updating the copyright years, and do so manually for the remaining two.

Then regenerate *-linux.xml using make, propagating the groups changes and
copyright years.

Tested on x86_64-linux.

Approved-By: Andrew Burgess <aburgess@redhat.com>