docs: kdump: add scp example to write out the dump file

Except cp and makedumpfile, add scp example to write out the dump file.

Link: https://lkml.kernel.org/r/1644324666-15947-3-git-send-email-yangtiezhu@loongson.cnSigned-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Xuefeng Li <lixuefeng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/admin-guide/kdump/kdump.rst

@@ -533,6 +533,10 @@ the following command::
 
    cp /proc/vmcore <dump-file>
 
+or use scp to write out the dump file between hosts on a network, e.g::
+
+   scp /proc/vmcore remote_username@remote_ip:<dump-file>
+
 You can also use makedumpfile utility to write out the dump file
 with specified options to filter out unwanted contents, e.g::