crash_dump: fix typo in function name read_key_from_user_keying

crash_dump: fix typo in function name read_key_from_user_keying

The function read_key_from_user_keying() is missing an 'r' in its name.
Fix the typo by renaming it to read_key_from_user_keyring().

Link: https://lkml.kernel.org/r/20260227230422.859423-1-thorsten.blum@linux.dev
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>