For Freescale QorIQ LS1021AQDS board, there is a SDIO interrupt
in the process of resume without inserting SD adapter because of
some unknown issue. But the driver doesn't assign sdio_irq_thread
pointer. This will block the resume of kernel. This patch is used
to avoid using NULL sdio_irq_thread pointer.
Signed-off-by: NYangbo Lu <yangbo.lu@freescale.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>