fbcon: Remove unused vblank cursor code

commit 1fa0b29f ("fbdev: Kill Atari vblank cursor blinking")

rendered vbl_cursor_cnt and therefore CURSOR_DRAW_DELAY unused in fbcon.c,
so remove them.

Signed-off-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>