Allow console input to be disabled

Added new CONFIG_DISABLE_CONSOLE define and GD_FLG_DISABLE_CONSOLE.

When CONFIG_DISABLE_CONSOLE is defined, setting
GD_FLG_DISABLE_CONSOLE disables all console input and output.

Signed-off-by: Mark Jackson <mpfj@mimc.co.uk>
diff --git a/include/asm-nios2/global_data.h b/include/asm-nios2/global_data.h
index cd17e08..db71324 100644
--- a/include/asm-nios2/global_data.h
+++ b/include/asm-nios2/global_data.h
@@ -47,6 +47,7 @@
 #define	GD_FLG_POSTFAIL	0x00008		/* Critical POST test failed		*/
 #define	GD_FLG_POSTSTOP	0x00010		/* POST seqeunce aborted		*/
 #define	GD_FLG_LOGINIT	0x00020		/* Log Buffer has been initialized	*/
+#define GD_FLG_DISABLE_CONSOLE	0x00040		/* Disable console (in & out)	 */
 
 #define DECLARE_GLOBAL_DATA_PTR     register gd_t *gd asm ("r15")