mmc: sdhci: Do not unnecessarily enable wakeup for SDIO card interrupt

Do not enable wakeup for SDIO card interrupt unless the SDIO function
driver has requested it which is indicated by mmc_card_wake_sdio_irq().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>