microblaze: Wire up dts configuration

    - enable OF control and embedded OF
    - set default device tree file name to 'microblaze'
    - add CPP to dtc proxy: board/xilinx/dts/microblaze.dts
    - add an empty but processable dts for microblaze-generic

Signed-off-by: Stephan Linz <linz@li-pro.net>
diff --git a/include/configs/microblaze-generic.h b/include/configs/microblaze-generic.h
index e20eb08..9a0f9a1 100644
--- a/include/configs/microblaze-generic.h
+++ b/include/configs/microblaze-generic.h
@@ -31,6 +31,11 @@
 #define	CONFIG_MICROBLAZE	1
 #define	MICROBLAZE_V5		1
 
+/* Open Firmware DTS */
+#define CONFIG_OF_CONTROL	1
+#define CONFIG_OF_EMBED		1
+#define CONFIG_DEFAULT_DEVICE_TREE microblaze
+
 /* linear flash memory */
 #ifdef XILINX_FLASH_START
 #define	FLASH