mlxsw: spectrum_nve: Remove easily triggerable warnings

It is possible to trigger a warning in mlxsw in case a flood entry which
mlxsw is not aware of is deleted from the VxLAN device. This is because
mlxsw expects to find a singly linked list where the flood entry is
present in.

Fix by removing these warnings for now.

Will re-add them in the next release after we teach mlxsw to ask for a
dump of FDB entries from the VxLAN device, once it is enslaved to a
bridge mlxsw cares about.

Fixes: 6e6030bd

 ("mlxsw: spectrum_nve: Implement common NVE core")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>