rv: Fix missing unlock on double nested monitors return path

rv: Fix missing unlock on double nested monitors return path

RV doesn't support nested monitors having children monitors themselves
and exits with the EINVAL code. However, it returns without unlocking
the rv_interface_lock.

Unlock the lock before returning from the initialisation function.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/20250402071351.19864-2-gmonaco@redhat.com
Fixes: cb85c660fcd4 ("rv: Add option for nested monitors and include sched")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@inria.fr>
Closes: https://lore.kernel.org/r/202503310200.UBXGitB4-lkp@intel.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>