Currently, if all TX descriptors are in use and IP stack calls K64F/K66F
ethernet driver link out, link out drops the packet. Added 10ms delay
to link out to wait for a descriptor to become available before dropping
the packet.
Changed K64F/K66F power up to return without waiting for link up i.e. for
the ethernet cable to be connected. This is needed for non-blocking use
of driver e.g. for using the driver from event queue.
TX pointer array was using RX ring length in its declaration.
Wasted memory if RX ring > TX ring, as is the default, but would
be broken if RX ring < TX ring.
Mika Leppänen
Kevin Bracey
Mahesh Mahadevan