blackfin: convert to use CONFIG_SYS_I2C framework

Signed-off-by: Scott Jiang <scott.jiang.linux@gmail.com>
diff --git a/include/configs/bf537-pnav.h b/include/configs/bf537-pnav.h
index 6c9a907..4f2b2cb 100644
--- a/include/configs/bf537-pnav.h
+++ b/include/configs/bf537-pnav.h
@@ -142,8 +142,8 @@
 /*
  * I2C settings
  */
+#define CONFIG_SYS_I2C
 #define CONFIG_SYS_I2C_ADI
-#define CONFIG_HARD_I2C		1
 
 
 /*