mmc: core: Prevent processing SDIO IRQs when the card is suspended

Processing of SDIO IRQs must obviously be prevented while the card is
system suspended, otherwise we may end up trying to communicate with an
uninitialized SDIO card.

Reports throughout the years shows that this is not only a theoretical
problem, but a real issue. So, let's finally fix this problem, by keeping
track of the state for the card and bail out before processing the SDIO
IRQ, in case the card is suspended.

Cc: stable@vger.kernel.org
Reported-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>