Revert "cleanup:  Remove HAVE_MULTIVOLUME from targets with HAVE_MULTIDRIVE"

This reverts commit a89bf68e889dd989e486b0a131618f69e5fc26c6.

HAVE_MULTIVOLUME && HAVE_MULTIDRIVE implicitly means "allow 4 volumes
per drive" whereas the normal MULTIDRIVE behavior is to only allow 1
volume per drive.
4 files changed