usb: move ehci_create_ich9_with_companions to hw/i386

This function is only needed when Q35 is in use.  Moving it to
the same file that uses it lets you disable the entire USB
subsystem in x86_64-softmmu.mak; of course doing that will
cause -usb to break horribly, but one thing at a time.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1545064358-4601-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
3 files changed