mmc: core: Extend mmc_of_parse() to check for mmc-ddr-3_3v

When mmc_of_parse() finds the binding, it sets the mmc cap,
MMC_CAP_3_3V_DDR, which informs the core whether eMMC DDR at 3.3V I/O is
supported by the mmc host.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Tested-by: Jan Glauber <jglauber@cavium.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>

drivers/mmc/core/host.c

@@ -301,6 +301,8 @@ int mmc_of_parse(struct mmc_host *host)
 	if (of_property_read_bool(np, "wakeup-source") ||
 	    of_property_read_bool(np, "enable-sdio-wakeup")) /* legacy */
 		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
+	if (of_property_read_bool(np, "mmc-ddr-3_3v"))
+		host->caps |= MMC_CAP_3_3V_DDR;
 	if (of_property_read_bool(np, "mmc-ddr-1_8v"))
 		host->caps |= MMC_CAP_1_8V_DDR;
 	if (of_property_read_bool(np, "mmc-ddr-1_2v"))