tracing: Free module_delta on freeing of persistent ring buffer

If a persistent ring buffer is created, a "module_delta" array is also
allocated to hold the module deltas of loaded modules that match modules
in the scratch area. If this buffer gets freed, the module_delta array is
not freed and causes a memory leak.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250401124525.1f9ac02a@gandalf.local.home


Fixes: 35a380dd ("tracing: Show last module text symbols in the stacktrace")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>