net/bonding: remove all slaves on close

net/bonding: remove all slaves on close

Some applications like OVS knows nothing about the
device type and wants to use same API to work with
all of them. But bond_pmd, unlike other pmds, requires
additional step (removing of all the slaves) before
closing the device.

In fact that bond_pmd automatically adds all the
devices from kvargs to bonding on configuration it
also should remove all of them on close.

This change is intended to have the same API for physical
and virtual devices. It allows us to handle virtual
devices in OVS in a common way.

Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Acked-by: Declan Doherty <declan.doherty@intel.com>