The sysfs SR-IOV functions are only needed when the kernel is built with
SR-IOV support.  Rather than put them in pci-sysfs.c under #ifdef
CONFIG_PCI_IOV, move them to iov.c, which is only compiled when
CONFIG_PCI_IOV=y.

Link: https://lore.kernel.org/r/20190813204513.4790-4-skunberg.kelsey@gmail.comSigned-off-by: Kelsey Skunberg <skunberg.kelsey@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Donald Dutile <ddutile@redhat.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>