mmc: core: add mmc-hs400-enhanced-strobe support

This patch introduce mmc-hs400-enhanced-strobe for platforms
which want to enable enhanced strobe function from DT if the
mmc host controller claims to support enhanced strobe.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 45cde8c..b836a27 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -302,6 +302,7 @@
 #define MMC_CAP2_SDIO_IRQ_NOTHREAD (1 << 17)
 #define MMC_CAP2_NO_WRITE_PROTECT (1 << 18)	/* No physical write protect pin, assume that card is always read-write */
 #define MMC_CAP2_NO_SDIO	(1 << 19)	/* Do not send SDIO commands during initialization */
+#define MMC_CAP2_HS400_ES	(1 << 20)	/* Host supports enhanced strobe */
 
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */