pci: fix iov.c kernel-doc warnings

Fix kernel-doc warning in iov.c:

  Warning(drivers/pci/iov.c:752): No description found for parameter 'numvfs'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Sorry-by: Don Dutile <ddutile@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>