scsi: lpfc: Cap NPIV vports to 256

[ Upstream commit 8b47ae69e049ae0b3373859d901f0334322f9fe9 ]

Depending on the chipset, the number of NPIV vports may vary and be in
excess of what most switches support (256). To avoid confusion with the
users, limit the reported NPIV vports to 256.

Additionally correct the 16G adapter which is reporting a bogus NPIV vport
number if the link is down.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>