dm: i2c: Add a message debug function

Add a way to dump the contents of an I2C message for debugging purposes.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>
diff --git a/include/i2c.h b/include/i2c.h
index 9300d97..a5498a3 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -473,6 +473,16 @@
 int i2c_chip_ofdata_to_platdata(const void *blob, int node,
 				struct dm_i2c_chip *chip);
 
+/**
+ * i2c_dump_msgs() - Dump a list of I2C messages
+ *
+ * This may be useful for debugging.
+ *
+ * @msg:	Message list to dump
+ * @nmsgs:	Number of messages
+ */
+void i2c_dump_msgs(struct i2c_msg *msg, int nmsgs);
+
 #ifndef CONFIG_DM_I2C
 
 /*