scsi: qla2xxx: Display 16G only as supported speeds for 3830c card

This card is unique and doesn't support lower speeds, hence update the fdmi
field to display 16G only.

Link: https://lore.kernel.org/r/20210908164622.19240-3-njavali@marvell.com


Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>