scsi: mpt3sas: Fail release cmnd if diag buffer is released

Return the diag buffer release command with -EINVAL status if the buffer is
already released.

Link: https://lore.kernel.org/r/1568379890-18347-10-git-send-email-sreekanth.reddy@broadcom.com
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpt3sas/mpt3sas_ctl.c

@@ -2235,7 +2235,7 @@ _ctl_diag_release(struct MPT3SAS_ADAPTER *ioc, void __user *arg)
 	    MPT3_DIAG_BUFFER_IS_RELEASED) {
 		ioc_err(ioc, "%s: buffer_type(0x%02x) is already released\n",
 			__func__, buffer_type);
-		return 0;
+		return -EINVAL;
 	}
 
 	request_data = ioc->diag_buffer[buffer_type];