docs: Fix names for PF and VF PCI device capabilities
docs: Fix names for PF and VF PCI device capabilities

The proper name for physical function capability is 'phys_function', not
'physical_function'. Likewise, a virtual function capability is
'virt_functions' rather than 'virtual_function'.

Signed-off-by: Jonathon Jongsma <c7254805a17bd5c41e24c3a278fcbf3afcdfb0fa@redhat.com>
Reviewed-by: Erik Skultety <2c14d38fa47c8799f1b9c16280abe27f8edfec6e@redhat.com>

crobinso/libvirt,zippy2/libvirt,jardasgit/libvirt,zippy2/libvirt,jardasgit/libvirt,libvirt/libvirt,zippy2/libvirt,nertpinx/libvirt,libvirt/libvirt,libvirt/libvirt,nertpinx/libvirt,olafhering/libvirt,nertpinx/libvirt,zippy2/libvirt,jardasgit/libvirt,crobinso/libvirt,jfehlig/libvirt,crobinso/libvirt,jfehlig/libvirt,olafhering/libvirt,jardasgit/libvirt,crobinso/libvirt,nertpinx/libvirt,jfehlig/libvirt,jfehlig/libvirt,nertpinx/libvirt,olafhering/libvirt,olafhering/libvirt,libvirt/libvirt,jardasgit/libvirt