Uses avbtool to sign vendor.img if BOARD_AVB_ENABLE is set.
It also allows appending additional arguments to avbtool via
BOARD_AVB_VENDOR_ADD_HASHTREE_FOOTER_ARGS.
e.g.,
BOARD_AVB_ENABLE := true
BOARD_AVB_VENDOR_ADD_HASHTREE_FOOTER_ARGS := --generate_fec
Bug: 35415839
Test: "make" with the above variables and use avbtool to check vbmeta is
appended to vendor.img
Test: "make dist" with the above variables
Change-Id: I8ada38dff3def6d34613e77c67944def8a49f464
8ee4a3db8c