video: atmel_lcdfb: fix platform data struct

Today we mix pdata and drivers data in the struct atmel_lcdfb_info
Fix it and introduce a new struct atmel_lcdfb_pdata for platform data only

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>