firewire: core: maintain phy packet receivers locally in cdev layer

The list of receivers for phy packet is used only by cdev layer, while it
is maintained as a member of fw_card structure.

This commit maintains the list locally in cdev layer.

Link: https://lore.kernel.org/r/20250915234747.915922-3-o-takashi@sakamocchi.jp


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