microblaze: Enable hush parser

With Hush parser is possible to change command line in dtb
Signed-off-by: NMichal Simek <monstr@monstr.eu>

include/configs/microblaze-generic.h

@@ -288,7 +288,7 @@
 #define	CONFIG_SYS_USR_EXCEP	/* user exception */
 #define CONFIG_SYS_HZ	1000
 
-#define	CONFIG_PREBOOT		"echo U-BOOT for $(hostname);setenv preboot;echo"
+#define	CONFIG_PREBOOT	"echo U-BOOT for ${hostname};setenv preboot;echo"
 
 #define	CONFIG_EXTRA_ENV_SETTINGS	"unlock=yes\0" /* hardware flash protection */\
 					"nor0=ml401-0\0"\
@@ -298,4 +298,10 @@
 
 #define CONFIG_CMDLINE_EDITING
 
+/* Use the HUSH parser */
+#define CONFIG_SYS_HUSH_PARSER
+#ifdef CONFIG_SYS_HUSH_PARSER
+#define CONFIG_SYS_PROMPT_HUSH_PS2 "> "
+#endif
+
 #endif	/* __CONFIG_H */