firewire: ohci: use devres for memory object of ohci structure

firewire: ohci: use devres for memory object of ohci structure

The managed device resource (devres) framework is convenient to maintain
lifetime of allocated memory object for device.

This commit utilizes the framework for the object of ohci structure. The
extra operation for power management is required in Apple PowerMac based
machines, thus release callback is assigned to the object to call the
operation.

Link: https://lore.kernel.org/r/20230604054451.161076-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>