scsi: aacraid: aachba: Replace snprintf() with the safer scnprintf() variant

There is a general misunderstanding amongst engineers that {v}snprintf()
returns the length of the data *actually* encoded into the destination
array. However, as per the C99 standard {v}snprintf() really returns
the length of the data that *would have been* written if there were
enough space for it. This misunderstanding has led to buffer-overruns
in the past. It's generally considered safer to use the {v}scnprintf()
variants in their place (or even sprintf() in simple cases). So let's
do that.

Link: https://lwn.net/Articles/69419/
Link: https://github.com/KSPP/linux/issues/105
Cc: Adaptec OEM Raid Solutions <[e-mail]>
Cc: PMC-Sierra, Inc <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/aacraid/aachba.c

···
 			sp[0] = INQD_PDT_DA;
 			sp[1] = scsicmd->cmnd[2];
 			sp[2] = 0;
-			sp[3] = snprintf(sp+4, sizeof(sp)-4, "%08X",
+			sp[3] = scnprintf(sp+4, sizeof(sp)-4, "%08X",
 				le32_to_cpu(get_serial_reply->uid));
 			scsi_sg_copy_from_buffer(scsicmd, sp,
 						 sizeof(sp));
···
 	/*
 	 *	This breaks array migration.
 	 */
-	return snprintf((char *)(data), sizeof(struct scsi_inq) - 4, "%08X%02X",
-			le32_to_cpu(dev->adapter_info.serial[0]), cid);
+	return scnprintf((char *)(data), sizeof(struct scsi_inq) - 4, "%08X%02X",
+			 le32_to_cpu(dev->adapter_info.serial[0]), cid);
 }
 
 static inline void set_sense(struct sense_data *sense_data, u8 sense_key,