Define a new replenish_flags bitmap to contain Boolean flags
associated with an endpoint's replenishing state.  Replace the
replenish_enabled field with a flag in that bitmap.  This is to
prepare for the next patch, which adds another flag.
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>