dm: define LOG_CATEGORY for all uclass

Define LOG_CATEGORY for all uclass to allow filtering with
log command.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/ufs/ufs-uclass.c b/drivers/ufs/ufs-uclass.c
index 034d14f..ceea30c 100644
--- a/drivers/ufs/ufs-uclass.c
+++ b/drivers/ufs/ufs-uclass.c
@@ -5,6 +5,8 @@
  * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com
  */
 
+#define LOG_CATEGORY UCLASS_UFS
+
 #include <common.h>
 #include "ufs.h"
 #include <dm.h>