lib.sh: move xbmkget() to git.sh

in cbmk, it's only used from there.

in lbmk, it's also used from vendor.sh.

however, i plan to further expand git.sh at
some point, tidying it up so that git cloning
is also done from xbmkget, with dlop=git and
git.sh would then be renamed to get.sh

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

mk

@@ -17,6 +17,7 @@ fi
 . "include/mrc.sh"
 . "include/rom.sh"
 . "include/release.sh"
+. "include/git.sh"
 
 main()
 {
@@ -34,7 +35,6 @@ main()
 
 main "$@" || exit 0
 
-. "include/git.sh"
 . "include/tree.sh"
 
 trees "$@" || exit 0