lcd_console: remove unused defines

CONSOLE_ROW_SECOND, CONSOLE_ROW_LAST, and
CONSOLE_SCROLL_SIZE are unused. Remove them.

Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>