scsi: fnic: Replace use of sizeof with standard usage

Remove cast and replace use of sizeof(struct) with standard usage of
sizeof.

Suggested-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: a63e78eb ("scsi: fnic: Add support for fabric based solicited requests and responses")
Reviewed-by: Sesidhar Baddela <sebaddel@cisco.com>
Reviewed-by: Arulprabhu Ponnusamy <arulponn@cisco.com>
Reviewed-by: Gian Carlo Boffa <gcboffa@cisco.com>
Reviewed-by: Arun Easi <aeasi@cisco.com>
Signed-off-by: Karan Tilak Kumar <kartilak@cisco.com>
Link: https://lore.kernel.org/r/20250225215056.4899-1-kartilak@cisco.com


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>