firewire: core: use helper macro to compare against current jiffies
The pattern of calling either time_before64() or time_after64() with
get_jiffies_64() can be replaced with the corresponding helper macros.
Link: https://lore.kernel.org/r/20250915024232.851955-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>