core, release: add sload.f2fs for otatools.zip

This also updates mkf2fsuserimg.sh to call sload.f2fs.

Change-Id: I245f6b3dfcd966fbc6783329d781375879fcd065
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
diff --git a/core/Makefile b/core/Makefile
index 2ff5acc..6a1f000 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -2139,6 +2139,7 @@
   $(HOST_OUT_EXECUTABLES)/mksquashfs \
   $(HOST_OUT_EXECUTABLES)/mkf2fsuserimg.sh \
   $(HOST_OUT_EXECUTABLES)/make_f2fs \
+  $(HOST_OUT_EXECUTABLES)/sload_f2fs \
   $(HOST_OUT_EXECUTABLES)/simg2img \
   $(HOST_OUT_EXECUTABLES)/e2fsck \
   $(HOST_OUT_EXECUTABLES)/build_verity_tree \