mmc: sdhci-esdhc-imx: fix cd regression for dt platform

Current card detect probe process is that when driver finds a valid
ESDHC_CD_GPIO, it will clear the quirk SDHCI_QUIRK_BROKEN_CARD_DETECTION
which is set by default for all esdhc/usdhc controllers.
Then host driver will know there's a valid card detect function.

Commit 8d86e4fc ("mmc: sdhci-esdhc-imx: Call mmc_of_parse()")
breaks GPIO CD function for dt platform that it will return directly
when find ESDHC_CD_GPIO for dt platform which result in the later wrongly
to keep SDHCI_QUIRK_BROKEN_CARD_DETECTION for all dt platforms.
Then MMC_CAP_NEEDS_POLL will be used instead even there's a valid
GPIO card detect.

This patch adds back this function and follows the original approach to
clear the quirk if find an valid CD GPIO for dt platforms.

Fixes: 8d86e4fc ("mmc: sdhci-esdhc-imx: Call mmc_of_parse()")
Signed-off-by: Dong Aisheng <aisheng.dong@freescale.com>
Reviewed-by: Johan Derycke <johan.derycke@barco.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>