Add e6000sw driver supporting Marvell 88E6352, 88E6172, 88E6176 switches. It needs to be attached to mdio interface, exporting SMI access functionality. e6000sw supports port-based VLAN configuration, per-port media changing, accessing PHY and switch registers.
e6000sw attaches miibuses and PHY drivers as children. Instead of typical tick as callout, kthread-based tick is used. This combined with SX locks allows MDIO read/write calls to sleep. It is expected, because this hardware requires long delays in SMI read/write procedures, which can not be handled by busy-waiting.