mmc: dw_mmc: Re-store SDIO IRQs mask at system resume

mmc: dw_mmc: Re-store SDIO IRQs mask at system resume

In cases when SDIO IRQs have been enabled, runtime suspend is prevented by
the driver. However, this still means dw_mci_runtime_suspend|resume() gets
called during system suspend/resume, via pm_runtime_force_suspend|resume().
This means during system suspend/resume, the register context of the dw_mmc
device most likely loses its register context, even in cases when SDIO IRQs
have been enabled.

To re-enable the SDIO IRQs during system resume, the dw_mmc driver
currently relies on the mmc core to re-enable the SDIO IRQs when it resumes
the SDIO card, but this isn't the recommended solution. Instead, it's
better to deal with this locally in the dw_mmc driver, so let's do that.

Tested-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>