scsi: ibmvfc: Add max_sectors module parameter

scsi: ibmvfc: Add max_sectors module parameter

There are some scenarios that can occur, such as performing an upgrade of
the virtual I/O server, where the supported max transfer of the backing
device for an ibmvfc HBA can change. If the max transfer of the backing
device decreases, this can cause issues with previously discovered
LUNs. This patch accomplishes two things.  First, it changes the default
ibmvfc max transfer value to 1MB.  This is generally supported by all
backing devices, which should mitigate this issue out of the box. Secondly,
it adds a module parameter, enabling a user to increase the max transfer
value to values that are larger than 1MB, as long as they have configured
these larger values on the virtual I/O server as well.

[mkp: fix checkpatch warnings]

Signed-off-by: Brian King <brking@linux.ibm.com>
Link: https://lore.kernel.org/r/20240903134708.139645-2-brking@linux.ibm.com
Reviewed-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>