memory: atmel-ebi: Fix smc cycle xlate converter

The converter function for translating ns timings in register values was
initialized with a wrong function pointer. This resulted in wrong
register values also for the setup and pulse registers when configuring
the EBI interface trough dts.

Includes a small fix in a comment of the smc driver, which was probably
just a copy'n'paste mistake.

Signed-off-by: Alexander Dahl <ada@thorsis.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>