trees and git.sh: tidy up global variables

some of the variables only initialised in git.sh are
also used in the trees script, which is technically ok
because git.sh is included from the trees script, but
it makes more sense to declare them in the latter.

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

script/trees

@@ -12,7 +12,7 @@ set -u -e
 cbmakeargs="UPDATED_SUBMODULES=1 CPUS=$XBMK_THREADS"
 eval `setvars "" xarch cdir defconfig cmakedir xlang mode makeargs elfdir cmd \
     project target target_dir targets xtree _f target1 bootstrapargs mkhelper \
-    autoconfargs listfile autogenargs btype tree`
+    autoconfargs listfile autogenargs btype tree rev tree_depend`
 
 main()
 {