mmc: dw_mmc: Drop redundant call to ->card_event callback

The ->card_event callback isn't being used by any of the dw_mmc variants.
It's likely a leftover from an earlier change, hence let's just drop the
redundant call to it.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>

drivers/mmc/host/dw_mmc.c

@@ -2606,8 +2606,6 @@ static void dw_mci_handle_cd(struct dw_mci *host)
 {
 	struct dw_mci_slot *slot = host->slot;
 
-	if (slot->mmc->ops->card_event)
-		slot->mmc->ops->card_event(slot->mmc);
 	mmc_detect_change(slot->mmc,
 		msecs_to_jiffies(host->pdata->detect_delay_ms));
 }