Fix the i2c frequency and default address in rsdproto board

rsdproto board support has wrong I2C frequency and wrong return value
handling.

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>
diff --git a/include/configs/rsdproto.h b/include/configs/rsdproto.h
index 814082c..40a05fa 100644
--- a/include/configs/rsdproto.h
+++ b/include/configs/rsdproto.h
@@ -92,8 +92,8 @@
 
 /* enable I2C */
 #define CONFIG_HARD_I2C        	1	/* I2C with hardware support */
-#define CFG_I2C_SPEED		400000	/* I2C speed and slave address */
-#define CFG_I2C_SLAVE		0x7F
+#define CFG_I2C_SPEED		50000	/* I2C speed and slave address */
+#define CFG_I2C_SLAVE		0x30
 
 
 /* system clock rate (CLKIN) - equal to the 60x and local bus speed */