IOCCSZ and IORCSZ are reserved for discovery controllers. Avoid checking
their values during identify controller phase.

Fixes: 2fcd3ab3 ("nvme-fabrics: check ioccsz and iorcsz")
Reported-by: Daniel Wagner <dwagner@suse.de>
Tested-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>