Reject if a value node is mixed with subkey node on same
parent key node.
A value node can not co-exist with subkey node under some key
node, e.g.
key = value
key.subkey = another-value
This is not be allowed because bootconfig API is not designed
to handle such case.
Link: http://lkml.kernel.org/r/158220115232.26565.7792340045009731803.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
