Makefile.in: Make recog.h depend on $(TREE_H) [PR111021]

Makefile.in: Make recog.h depend on $(TREE_H) [PR111021]

Commit r14-3093 introduced a random build failure on
build/gencondmd.cc building.  Since r14-3093 make recog.h
include tree.h, which further includes (depends on) some
files that are generated during the building, such as:
all-tree.def, tree-check.h etc, when building file
build/gencondmd.cc, the build can fail if these dependences
are not ready.  So this patch is to teach this dependence.

Thank Jan-Benedict Glaw for testing this!

	PR bootstrap/111021

gcc/ChangeLog:

	* Makefile.in (RECOG_H): Add $(TREE_H) as dependence.