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/i2c/i2c-emul-uclass.c b/drivers/i2c/i2c-emul-uclass.c
index 7917b63..aeec6aa 100644
--- a/drivers/i2c/i2c-emul-uclass.c
+++ b/drivers/i2c/i2c-emul-uclass.c
@@ -3,6 +3,8 @@
  * Copyright (c) 2014 Google, Inc
  */
 
+#define LOG_CATEGORY UCLASS_I2C_EMUL
+
 #include <common.h>
 #include <dm.h>
 #include <i2c.h>
diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
index be56785..04c8850 100644
--- a/drivers/i2c/i2c-uclass.c
+++ b/drivers/i2c/i2c-uclass.c
@@ -3,6 +3,8 @@
  * Copyright (c) 2014 Google, Inc
  */
 
+#define LOG_CATEGORY UCLASS_I2C
+
 #include <common.h>
 #include <dm.h>
 #include <errno.h>
diff --git a/drivers/i2c/muxes/i2c-mux-uclass.c b/drivers/i2c/muxes/i2c-mux-uclass.c
index dbca409..a5d1bb0 100644
--- a/drivers/i2c/muxes/i2c-mux-uclass.c
+++ b/drivers/i2c/muxes/i2c-mux-uclass.c
@@ -4,6 +4,8 @@
  * Written by Simon Glass <sjg@chromium.org>
  */
 
+#define LOG_CATEGORY UCLASS_I2C_MUX
+
 #include <common.h>
 #include <dm.h>
 #include <errno.h>