OMAP: stalker: Remove LCD device from board file

OMAP3 Stalker board has definitions for LCD, but uses the generic driver
without any information what kind of LCD it has. The board should use a
particular panel type from panel-generic-dpi driver, not the generic
one.

As I haven't gotten response the signer-off of stalker board about the
issue, this patch removes the LCD support from the board file. This will
allow us to clean up the panel-generic-dpi driver and make it support
only fixed size panels.

CC: Jason Lam <lzg@ema-tech.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>