ARM: OMAP1: ams-delta: Drop unused symbols from the board header

Those bitmap symbols defining pins of latch2 register, used with
read()/write() calls before the latch was converted to a GPIO device,
have been obsoleted by integer symbols defined inside the board file.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>