ARM: dts: Delete bogus reference to the charlcd

The EB MP board probably has a character LCD but the board manual does
not really state which IRQ it has assigned to this device. The invalid
assignment was a mistake by me during submission of the DTSI where I was
looking for the reference, didn't find it and didn't fill it in.

Delete this for now: it can probably be fixed but that requires access
to the actual board for some trial-and-error experiments.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>