dm: video: correctly set the cursor position

The terminal escape sequence ESC [ <x> ; <y> H is used to set the cursor
position. According to the ECMA 48 standard the upper left corner in the
escape sequences is [1, 1]. The video uclass uses [0, 0] as upper left
corner.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>