mmc: mxs-mmc: Enable MMC_CAP_ERASE

According to the i.MX23/28 reference manuals both mmc interfaces support
the MMC_ERASE command. So enable this capability in the driver to allow
erase/discard/trim requests.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/mxs-mmc.c

@@ -648,7 +648,8 @@ static int mxs_mmc_probe(struct platform_device *pdev)
 	/* set mmc core parameters */
 	mmc->ops = &mxs_mmc_ops;
 	mmc->caps = MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED |
-		    MMC_CAP_SDIO_IRQ | MMC_CAP_NEEDS_POLL | MMC_CAP_CMD23;
+		    MMC_CAP_SDIO_IRQ | MMC_CAP_NEEDS_POLL | MMC_CAP_CMD23 |
+		    MMC_CAP_ERASE;
 
 	host->broken_cd = of_property_read_bool(np, "broken-cd");