firewire: core: add tracepoint event for handling bus reset

The core function expects hardware drivers to call
fw_core_handle_bus_reset() when changing bus topology. The 1394 OHCI
driver calls it when handling selfID event as a result of any bus-reset.

This commit adds a tracepoints event for it.

Link: https://lore.kernel.org/r/20240501073238.72769-6-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>