firewire: core: use cleanup function to release cached configuration ROM

firewire: core: use cleanup function to release cached configuration ROM

When returning from read_config_rom() function, the allocated buffer and
the previous buffer for configuration ROM should be released. The cleanup
function is useful in the case.

This commit uses the cleanup function to remove goto statements.

Link: https://lore.kernel.org/r/20251020115810.92839-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>