scsi: qedf: Cleanup the type of io_log->op

We store sc_cmd->cmnd[0] which is an unsigned char in io_log->op so
this should also be unsigned char.  The other thing is that this is
displayed in the debugfs:

	seq_printf(s, "0x%02x:", io_log->op);

Smatch complains that the formatting won't work for negative values so
changing it to unsigned silences that warning as well.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Chad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qedf/qedf.h

@@ -259,7 +259,7 @@ struct qedf_io_log {
 	uint16_t task_id;
 	uint32_t port_id; /* Remote port fabric ID */
 	int lun;
-	char op; /* SCSI CDB */
+	unsigned char op; /* SCSI CDB */
 	uint8_t lba[4];
 	unsigned int bufflen; /* SCSI buffer length */
 	unsigned int sg_count; /* Number of SG elements */