megaraid_sas: Print critical firmware event messages

Print firmware events in human-readable form. This will help users track
any critical firmware events without special application support.

Sample syslogd output:

megaraid_sas 0000:02:00.0: 8619 (491648347s/0x0020/WARN) - Controller temperature threshold exceeded. This may indicate inadequate system cooling. Switching to low performance mode.

The format of logged events is:

"<pci_dev_id>: <sequence_number> (<timestamp>/<locale>/<class>) - <description>"

Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 5db31c6..ccda60d 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -273,6 +273,16 @@
 	MFI_STAT_INVALID_STATUS = 0xFF
 };
 
+enum mfi_evt_class {
+	MFI_EVT_CLASS_DEBUG =		-2,
+	MFI_EVT_CLASS_PROGRESS =	-1,
+	MFI_EVT_CLASS_INFO =		0,
+	MFI_EVT_CLASS_WARNING =		1,
+	MFI_EVT_CLASS_CRITICAL =	2,
+	MFI_EVT_CLASS_FATAL =		3,
+	MFI_EVT_CLASS_DEAD =		4
+};
+
 /*
  * Crash dump related defines
  */