mmc: sdhci-xenon: Support HS400 Enhanced Strobe feature

Support HS400 Enhanced Strobe feature in Xenon.

Enable Enhanced Strobe together with Data Strobe.
Disable Enhanced Strobe when eMMC is not in HS400 mode.

Signed-off-by: Hu Ziji <huziji@marvell.com>
Signed-off-by: Zhoujie Wu <zjwu@marvell.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-xenon.h

@@ -33,6 +33,7 @@
 #define XENON_TUNING_STEP_DIVIDER		BIT(6)
 
 #define XENON_SLOT_EMMC_CTRL			0x0130
+#define XENON_ENABLE_RESP_STROBE		BIT(25)
 #define XENON_ENABLE_DATA_STROBE		BIT(24)
 
 #define XENON_SLOT_RETUNING_REQ_CTRL		0x0144