rv: Add license identifiers to monitor files

Some monitor files like the main header and the Kconfig are missing the
license identifier.

Add it to those and make sure the automatic generation script includes
the line in newly created monitors.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/20250218123121.253551-3-gmonaco@redhat.com


Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>