console: Add a way to quit pager with no further output

Add support for pressing 'q' to throw away any further output until the
prompt is reached.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/cli_readline.c

@@ -654,6 +654,7 @@ int cli_readline_into_buffer(const char *const prompt, char *buffer,
 	static int initted;
 	bool old_bypass;
 
+	pager_clear_quit(gd_pager());
 	old_bypass = pager_set_bypass(gd_pager(), true);
 
 	/*