net: rds: Use time_after() for time comparison

To be future-proof and for better readability the time comparisons are modified
to use time_after() instead of raw math.

Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

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