inject.sh: split to vendor.sh the download parts

to the extent feasible, keep lbmk-specific parts on
inject.sh to a minimum. this will later be used to
re-sync cbmk's inject.sh with lbmk's, because cbmk's
one doesn't handle vendor files.

the way this is designed now, with this patch, will
make cherry-picking lbmk to cbmk easier in the future,
when keeping this part of cbmk in sync with lbmk.

Signed-off-by: Leah Rowe <leah@libreboot.org>

mk

@@ -12,6 +12,7 @@ fi
 
 . "include/lib.sh"
 . "include/init.sh"
+. "include/vendor.sh"
 . "include/inject.sh"
 . "include/mrc.sh"
 . "include/rom.sh"