smc: make smc_rx_wait_data() generic

Turn smc_rx_wait_data into a generic function that can be used at various
instances to wait on traffic to complete with varying criteria.

Signed-off-by: Stefan Raspl <raspl@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com&gt;&lt;>
Signed-off-by: David S. Miller <davem@davemloft.net>