firewire: ohci: use helper inline functions to serialize/deserialize self ID packet
This commit replaces the existing implementation with the helper
functions for self ID packet.
Link: https://lore.kernel.org/r/20240605235155.116468-10-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>