scsi: mpt3sas: fix possible memory leak.

In ioctl exit path driver refers ioc_list to free memory associated with
diag buffers and event_log pointer used to save events by driver.
If ctl_exit() func is called after unregistering driver, then ioc_list will
be empty and hence driver will not be able to free the allocated memory
which in turn causes memory leak.
So call ctl_exit() function before unregistering mpt3sas driver.

Signed-off-by: Chaitra P B <chaitra.basappa@broadcom.com>
Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpt3sas/mpt3sas_scsih.c

@@ -11287,10 +11287,10 @@ _mpt3sas_exit(void)
 	pr_info("mpt3sas version %s unloading\n",
 				MPT3SAS_DRIVER_VERSION);
 
-	pci_unregister_driver(&mpt3sas_driver);
-
 	mpt3sas_ctl_exit(hbas_to_enumerate);
 
+	pci_unregister_driver(&mpt3sas_driver);
+
 	scsih_exit();
 }