keystone2: add keystone multicore navigator driver

keystone2: add keystone multicore navigator driver

Multicore navigator consists of Network Coprocessor (NetCP) and
Queue Manager sub system. More details on the hardware can
be obtained from the following links:-

Network Coprocessor: http://www.ti.com/lit/pdf/sprugz6
Multicore Navigator: http://www.ti.com/lit/pdf/sprugr9

Multicore navigator driver implements APIs to configure
the Queue Manager and NetCP Pkt DMA.

Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: WingMan Kwok <w-kwok2@ti.com>
Acked-by: Tom Rini <trini@ti.com>