video: truetype: Handle rendering of bitmap fonts

Complete the support for this feature by dealing with rendering, the
moving to a particular row/column and scrolling.

Provide a simple test to check that things look right.

Allow omitting the font name to request the default font.

Fix an errant tab nearby.

Co-developed-by: Claude <noreply@anthropic.com>
Signed-off-by: Simon Glass <sjg@chromium.org>

cmd/font.c

@@ -31,9 +31,6 @@ static int do_font_select(struct cmd_tbl *cmdtp, int flag, int argc,
 	uint size = 0;
 	int ret;
 
-	if (argc < 2)
-		return CMD_RET_USAGE;
-
 	if (uclass_first_device_err(UCLASS_VIDEO_CONSOLE, &dev))
 		return CMD_RET_FAILURE;
 	name = argv[1];