scsi: bnx2fc: fix incorrect cast to u64 on shift operation

Currently an int is being shifted and the result is being cast to a u64
which leads to undefined behaviour if the shift is more than 31 bits. Fix
this by casting the integer value 1 to u64 before the shift operation.

Addresses-Coverity: ("Bad shift operation")
Fixes: 7b594769 ("[SCSI] bnx2fc: Handle REC_TOV error code from firmware")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>