IB/core: Delete lower netdevice default GID entries in bonding scenario

When NETDEV_CHANGEUPPER event occurs, lower device is not yet established
as slave of the master, and when upper device is bond device, default GID
entries not deleted.

Due to this, when bond device is fully configured, default GID entries of
bond device cannot be added as default GID entries are occupied by the
lower netdevice. This is incorrect.

Default GID entries should really be of bond netdevice because in all RoCE
GIDs (default or IP), MAC address of the bond device will be used.  It is
confusing to have default GID of netdevice which is not really used for
any purpose.

Therefore, as first step, implement
(a) filter function which filters if a CHANGEUPPER event netdevice and
    associated upper device is master device or not.
(b) callback function which deletes the default GIDs of lower (event
    netdevice).

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>