Staging: ti-st: make use of linux err codes

remove custom error code definitions from the header and
make use of the agreed upon linux error codes.

Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/ti-st/st_ll.c b/drivers/staging/ti-st/st_ll.c
index 0685a10..6bc0759 100644
--- a/drivers/staging/ti-st/st_ll.c
+++ b/drivers/staging/ti-st/st_ll.c
@@ -127,9 +127,9 @@
 		break;
 	default:
 		pr_err(" unknown input/state ");
-		return ST_ERR_FAILURE;
+		return -1;
 	}
-	return ST_SUCCESS;
+	return 0;
 }
 
 /* Called from ST CORE to initialize ST LL */