firewire: ohci: Misleading kfree in ohci.c::pci_probe/remove

It seems drivers/firewire/ohci.c is making some optimistic assumptions
about struct fw_ohci and that member "card" will always remain the first
member of the struct.
Plus it's probably going to confuse a lot of static code analyzers too.

So I wonder if there is a good reason not to free the ohci struct just
like it was allocated instead of the tricky &ohci->card way?

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>

It is perhaps just a rudiment from before mainline submission of the
driver.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>