mmc: pwrseq: add mmc-pwrseq file to provide a generic interface

Add mmc-pwrseq file to provide a generic interface.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index f8ea921..f8ca52e 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -18,6 +18,13 @@
 	help
 	  Enable write access to MMC and SD Cards
 
+config MMC_PWRSEQ
+	bool "HW reset support for eMMC"
+	depends on PWRSEQ
+	help
+	  Ths select Hardware reset support aka pwrseq-emmc for eMMC
+	  devices.
+
 config MMC_BROKEN_CD
 	bool "Poll for broken card detection case"
 	help