AT91: add platform parameters for atmel_tsadcc in at91sam9rlek

Setup platform parameters in at91sam9rl-ek board to be passed to
atmel_tsadcc touchscreen.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>