scsi: megaraid: fix format-overflow warning

gcc-7 complains that the firmware version strings might overflow
for some values:

drivers/scsi/megaraid.c: In function 'megaraid_probe_one':
drivers/scsi/megaraid.c:314:33: error: '%d' directive writing between 1 and 2 bytes into a region of size between 1 and 2 [-Werror=format-overflow=]
drivers/scsi/megaraid.c:314:33: note: directive argument in the range [0, 15]
drivers/scsi/megaraid.c:314:3: note: 'sprintf' output between 7 and 9 bytes into a destination of size 7
drivers/scsi/megaraid.c:320:35: error: '%d' directive writing between 1 and 2 bytes into a region of size between 1 and 2 [-Werror=format-overflow=]
drivers/scsi/megaraid.c:320:35: note: directive argument in the range [0, 15]
drivers/scsi/megaraid.c:320:3: note: 'sprintf' output between 7 and 9 bytes into a destination of size 7

This makes the code use a truncating snprintf() instead, which shuts
up that warning.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/megaraid.c

@@ -311,13 +311,15 @@ mega_query_adapter(adapter_t *adapter)
 	   right 8 bits making them zero. This 0 value was hardcoded to fix
 	   sparse warnings. */
 	if (adapter->product_info.subsysvid == PCI_VENDOR_ID_HP) {
-		sprintf (adapter->fw_version, "%c%d%d.%d%d",
+		snprintf(adapter->fw_version, sizeof(adapter->fw_version),
+			 "%c%d%d.%d%d",
 			 adapter->product_info.fw_version[2],
 			 0,
 			 adapter->product_info.fw_version[1] & 0x0f,
 			 0,
 			 adapter->product_info.fw_version[0] & 0x0f);
-		sprintf (adapter->bios_version, "%c%d%d.%d%d",
+		snprintf(adapter->bios_version, sizeof(adapter->fw_version),
+			 "%c%d%d.%d%d",
 			 adapter->product_info.bios_version[2],
 			 0,
 			 adapter->product_info.bios_version[1] & 0x0f,