VMCI: Add PCI as a dependency

Add PCI as a dependency to our build, since we always compile in the guest-side
PCI device support.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andy King <acking@vmware.com>
Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>