gdb: syscalls: Update .xml.in files for some archs

Make use of the script update-linux-from-src.sh to regenerate the Linux
syscall group info against Linux git commit d206a76d7d27 which will be
released in v6.8.

Like this:

  $ git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux.git
  $ git clone https://sourceware.org/git/binutils-gdb.git

 gdb.git
  $ cd gdb.git/gdb/syscalls/
  $ ./update-linux-from-src.sh ~/linux.git/

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Approved-By: John Baldwin <jhb@FreeBSD.org>