People are confused by "make vmlinux/bzImage/..." building modules at
the same time. So revert to the old behavior.

"make bzImage modules" builds bzImage and modules, using only one pass
of descending into subdirs.

"make" or "make all" builds a standard target of "vmlinux modules". On
i386 this is extended to do "bzImage modules", which seems to be the most
sensible default.