In some cases, a NULL pointer dereference happens because data is NULL when
STATE_END_REQUEST case is reached in atmci_tasklet_func.

Cc: <stable@vger.kernel.org> # 3.9+
Signed-off-by: NRodolfo Giometti <giometti@enneenne.com>
Acked-by: NLudovic Desroches <ludovic.desroches@atmel.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NChris Ball <cjb@laptop.org>