rds: update correct congestion map for loopback transport

rds: update correct congestion map for loopback transport

Loopback transport delivers data directly to the destination
socket since destination is always local to the machine.
The connection data structure passed to an internal
initializer API rds_inc_init() is from send side (unlike the
usual call to APIs from receive path when receive side
connection data structure is passed).

This inconsistency causes an update of the incorrect
congestion map when marking destination port congested when
loopback transport is used (which is when one or both end(s)
of a RDS connection has an IP loopback address).

The fix it to ensure correct map is updated, that of the
destination IP regardless of delivery coming from send side
of loopback transport or receive side of other transports.

Orabug: 29175685

Signed-off-by: Mukesh Kacker <mukesh.kacker@oracle.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>