console: Remember if ctrlc is disabled in console_tstc()

We don't necessarily want to re-enable ctrl-c if it was already disabled
when calling tstc().

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/console.c b/common/console.c
index 2ba33dc..36c0568 100644
--- a/common/console.c
+++ b/common/console.c
@@ -196,20 +196,21 @@
 {
 	int i, ret;
 	struct stdio_dev *dev;
+	int prev;
 
-	disable_ctrlc(1);
+	prev = disable_ctrlc(1);
 	for (i = 0; i < cd_count[file]; i++) {
 		dev = console_devices[file][i];
 		if (dev->tstc != NULL) {
 			ret = dev->tstc(dev);
 			if (ret > 0) {
 				tstcdev = dev;
-				disable_ctrlc(0);
+				disable_ctrlc(prev);
 				return ret;
 			}
 		}
 	}
-	disable_ctrlc(0);
+	disable_ctrlc(prev);
 
 	return 0;
 }