[SPARC64]: Assorted LDC bug cures.

1) LDC_MODE_RELIABLE is deprecated an unused by anything, plus
   it and LDC_MODE_STREAM were mis-numbered.

2) read_stream() should try to read as much as possible into
   the per-LDC stream buffer area, so do not trim the read_nonraw()
   length by the caller's size parameter.

3) Send data ACKs when necessary in read_nonraw().

4) In read_nonraw() when we get a pure ACK, advance the RX head
   unconditionally past it.

5) Provide the ACKID field in the ldcdgb() packet dump in read_nonraw().
   This helps debugging stream mode LDC channel problems.

6) Decrease verbosity of rx_data_wait() so that it is more useful.
   A debugging message each loop iteration is too much.

7) In process_data_ack() stop the loop checking when we hit lp->tx_tail
   not lp->tx_head.

8) Set the seqid field properly in send_data_nack().

Signed-off-by: David S. Miller <davem@davemloft.net>