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>

board/xilinx/dts/microblaze.dts

@@ -0,0 +1 @@
+/include/ BOARD_DTS

board/xilinx/microblaze-generic/dts/microblaze.dts

@@ -0,0 +1,7 @@
+/dts-v1/;
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+	aliases {
+	} ;
+} ;

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