RDS: Stop supporting old cong map sending method

We now ask the transport to give us a rm for the congestion
map, and then we handle it normally. Previously, the
transport defined a function that we would call to send
a congestion map.

Convert TCP and loop transports to new cong map method.

Signed-off-by: Andy Grover <andy.grover@oracle.com>

diff --cc net/rds/ib.c
Simple merge

diff --cc net/rds/iw.c
Simple merge

diff --cc net/rds/loop.c
Simple merge

diff --cc net/rds/rds.h
Simple merge

diff --cc net/rds/send.c
Simple merge

diff --cc net/rds/tcp.c
Simple merge

diff --cc net/rds/tcp.h
Simple merge

diff --cc net/rds/tcp_send.c
Simple merge