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/common/console.c b/common/console.c
index cfcaeb8..56d9118 100644
--- a/common/console.c
+++ b/common/console.c
@@ -162,6 +162,11 @@
 
 int getc (void)
 {
+#ifdef CONFIG_DISABLE_CONSOLE
+	if (gd->flags & GD_FLG_DISABLE_CONSOLE)
+		return 0;
+#endif
+
 	if (gd->flags & GD_FLG_DEVINIT) {
 		/* Get from the standard input */
 		return fgetc (stdin);
@@ -173,6 +178,11 @@
 
 int tstc (void)
 {
+#ifdef CONFIG_DISABLE_CONSOLE
+	if (gd->flags & GD_FLG_DISABLE_CONSOLE)
+		return 0;
+#endif
+
 	if (gd->flags & GD_FLG_DEVINIT) {
 		/* Test the standard input */
 		return ftstc (stdin);
@@ -189,6 +199,11 @@
 		return;
 #endif
 
+#ifdef CONFIG_DISABLE_CONSOLE
+	if (gd->flags & GD_FLG_DISABLE_CONSOLE)
+		return;
+#endif
+
 	if (gd->flags & GD_FLG_DEVINIT) {
 		/* Send to the standard output */
 		fputc (stdout, c);
@@ -205,6 +220,11 @@
 		return;
 #endif
 
+#ifdef CONFIG_DISABLE_CONSOLE
+	if (gd->flags & GD_FLG_DISABLE_CONSOLE)
+		return;
+#endif
+
 	if (gd->flags & GD_FLG_DEVINIT) {
 		/* Send to the standard output */
 		fputs (stdout, s);