core+tools: support specifying F2FS as the fstype for userdata

- Support TARGET_USERIMAGES_USE_F2FS.
- Support BOARD_USERDATAIMAGE_FILE_SYSTEM_TYPE.
- Support "userdata_fs_type" in the prop dict.
- Update build_image to recognize f2fs and call the correct command.

Change-Id: If31cc8bd235f93a4c7814fab36e6e2d13d3037ad
Signed-off-by: JP Abgrall <jpa@google.com>

tools/releasetools/common.py

@@ -968,7 +968,8 @@ def ComputeDifferences(diffs):
 
 # map recovery.fstab's fs_types to mount/format "partition types"
 PARTITION_TYPES = { "yaffs2": "MTD", "mtd": "MTD",
-                    "ext4": "EMMC", "emmc": "EMMC" }
+                    "ext4": "EMMC", "emmc": "EMMC",
+                    "f2fs": "EMMC" }
 
 def GetTypeAndDevice(mount_point, info):
   fstab = info["fstab"]