mmc: host: sdhci-esdhc-imx: add wakeup feature for GPIO CD pin

When use the specific GPIO to detect the card insert/remove, we can
also add the GPIO as a wakeup source. When system suspend, insert or
remove the card can wakeup the system.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/1590547175-15070-1-git-send-email-haibo.chen@nxp.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>