microblaze: Avoid compile error on systems without cfi flash

Use XILINX_FLASH_START to set/unset FLASH and RAMENV.

Error:
board.c: In function 'board_init':
board.c:134: error: 'XILINX_FLASH_START' undeclared (first use in this function)
board.c:134: error: (Each undeclared identifier is reported only once
board.c:134: error: for each function it appears in.)

Signed-off-by: Stephan Linz <linz@li-pro.net>
Signed-off-by: Michal Simek <monstr@monstr.eu>

include/configs/microblaze-generic.h

@@ -31,6 +31,15 @@
 #define	CONFIG_MICROBLAZE	1
 #define	MICROBLAZE_V5		1
 
+/* linear flash memory */
+#ifdef XILINX_FLASH_START
+#define	FLASH
+#undef	RAMENV	/* hold environment in flash */
+#else
+#undef	FLASH
+#define	RAMENV	/* hold environment in RAM */
+#endif
+
 /* uart */
 #ifdef XILINX_UARTLITE_BASEADDR
 # define CONFIG_XILINX_UARTLITE
@@ -164,9 +173,6 @@
 /* stack */
 #define	CONFIG_SYS_INIT_SP_OFFSET	CONFIG_SYS_MALLOC_BASE
 
-/*#define	RAMENV */
-#define	FLASH
-
 #ifdef FLASH
 # define CONFIG_SYS_FLASH_BASE		XILINX_FLASH_START
 # define CONFIG_SYS_FLASH_SIZE		XILINX_FLASH_SIZE