When a too small framebuffer is given, the atmel_lcdfb_check_var
silently fails.
Adding an error message will save some head scratching.
Signed-off-by: NRichard Genoud <richard.genoud@gmail.com>
Signed-off-by: NJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>