mmc: atmel-mci: Release mmc resources on failure in probe

This change takes care of releasing mmc resources on error cases in
probe function which was missing. Also release timer in remove function.

Signed-off-by: Pramod Gurav <pramod.gurav@smartplayin.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>