Enable f2fs sparse images.

This is relevant now that images are built as f2fs instead.

Test: make dist -j
Change-Id: If55cda438d321f38b5975fed020e09cd32ee01f0
diff --git a/shared/BoardConfig.mk b/shared/BoardConfig.mk
index aefeff5..f2a8bea 100644
--- a/shared/BoardConfig.mk
+++ b/shared/BoardConfig.mk
@@ -62,7 +62,7 @@
 
 # Make the userdata partition 4.25G to accomodate ASAN and CTS
 BOARD_USERDATAIMAGE_PARTITION_SIZE := 4563402752
-TARGET_USERIMAGES_SPARSE_F2FS_DISABLED := true
+TARGET_USERIMAGES_SPARSE_F2FS_DISABLED := false
 BOARD_USERDATAIMAGE_FILE_SYSTEM_TYPE := f2fs
 TARGET_USERIMAGES_USE_F2FS := true