nvme-fc: shorten reconnect delay if possible for FC

nvme-fc: shorten reconnect delay if possible for FC

We've had several complaints about a 10s reconnect delay (the default)
when there was an error while there is connectivity to a subsystem.
The max_reconnects and reconnect_delay are set in common code prior to
calling the transport to create the controller.

This change checks if the default reconnect delay is being used, and if
so, it adjusts it to a shorter period (2s) for the nvme-fc transport.
It does so by calculating the controller loss tmo window, changing the
value of the reconnect delay, and then recalculating the maximum number
of reconnect attempts allowed.

Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>