firewire: core: rename cause flag of tracepoints event

The flag of FW_ISO_CONTEXT_COMPLETIONS_CAUSE_IRQ directly causes hardIRQ
request by 1394 OHCI hardware when the corresponding isochronous packet is
transferred, however it is not so directly associated to hardIRQ
processing itself.

This commit renames the flag so that it relates to interrupt parameter of
internal packet data.

Link: https://lore.kernel.org/r/20240912133038.238786-6-o-takashi@sakamocchi.jp


Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>