net: mana: Add handler for sriov configure

Add callback function for the pci_driver / sriov_configure.

It asks the NIC to provide certain number of VFs, or disable
VFs if the request is zero.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Link: https://patch.msgid.link/20260710192735.2921300-1-haiyangz@linux.microsoft.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>