net: ipa: replenish after delivering payload

Replenishing is now solely driven by whether transactions are
available for a channel, and it doesn't really matter whether
we replenish before or after we deliver received packets to the
network stack.

Replenishing before delivering the payload adds a little latency.
Eliminate that by requesting a replenish after the payload is
delivered.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>