[libata] sata_vsc: fix inconsistent NULL checking

Also, cleanup interrupt mask content and note in Kconfig that this
driver supports the Intel 31244.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 5c94a5d..4035920 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -595,10 +595,10 @@
 	  If unsure, say N.
 
 config SCSI_SATA_VITESSE
-	tristate "VITESSE VSC-7174 SATA support"
+	tristate "VITESSE VSC-7174 / INTEL 31244 SATA support"
 	depends on SCSI_SATA && PCI
 	help
-	  This option enables support for Vitesse VSC7174 Serial ATA.
+	  This option enables support for Vitesse VSC7174 and Intel 31244 Serial ATA.
 
 	  If unsure, say N.