Convert CONFIG_CMD_YAFFS2 to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_YAFFS2

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

cmd/Kconfig

@@ -1369,6 +1369,17 @@ config CMD_SCSI
 	  scan the bus, reset the bus, read and write data and get information
 	  about devices.
 
+config CMD_YAFFS2
+	bool "yaffs2 - Access of YAFFS2 filesystem"
+	depends on YAFFS2
+	default y
+	help
+	  This provides commands for accessing a YAFFS2 filesystem. Yet
+	  Another Flash Filesystem 2 is a filesystem designed specifically
+	  for NAND flash. It incorporates bad-block management and ensures
+	  that device writes are sequential regardless of filesystem
+	  activity.
+
 endmenu
 
 menu "Debug commands"

cmd/Makefile

@@ -132,7 +132,7 @@ obj-$(CONFIG_CMD_FS_UUID) += fs_uuid.o
 obj-$(CONFIG_CMD_USB_MASS_STORAGE) += usb_mass_storage.o
 obj-$(CONFIG_CMD_THOR_DOWNLOAD) += thordown.o
 obj-$(CONFIG_CMD_XIMG) += ximg.o
-obj-$(CONFIG_YAFFS2) += yaffs2.o
+obj-$(CONFIG_CMD_YAFFS2) += yaffs2.o
 obj-$(CONFIG_CMD_SPL) += spl.o
 obj-$(CONFIG_CMD_ZIP) += zip.o
 obj-$(CONFIG_CMD_ZFS) += zfs.o

fs/Kconfig

@@ -18,4 +18,6 @@ source "fs/ubifs/Kconfig"
 
 source "fs/cramfs/Kconfig"
 
+source "fs/yaffs2/Kconfig"
+
 endmenu

fs/yaffs2/Kconfig

@@ -0,0 +1,7 @@
+config YAFFS2
+	bool "YAFFS2 filesystem support"
+	help
+	  This provides access to YAFFS2 filesystems. Yet Another Flash
+	  Filesystem 2 is a filesystem designed specifically for NAND flash.
+	  It incorporates bad-block management and ensures that device
+	  writes are sequential regardless of filesystem activity.