Fix Atmel LCD controller endianess for AVR32 processors

The Atmel lcd controller is used on Atmel's AT91 (little endian) and
AVR32 (big endian) platforms.

As such, the controller can handle both big and little endian memory.

This patch fixes the driver for the AVR32 platform.

Signed-off-by: Mark Jackson <mpfj@mimc.co.uk>