The entries in each IPA routing table are divided between the modem
and the AP.  The modem always gets some number of entries located at
the base of the table; the AP gets all those that follow.

There's no reason to think the modem will use anything different
from the first entries in a routing table, so:
  - Get rid of IPA_ROUTE_MODEM_MIN (just assume it's 0)
  - Get rid of IPA_ROUTE_AP_MIN (just assume it's IPA_ROUTE_MODEM_COUNT)
And finally:
  - Open-code IPA_ROUTE_AP_COUNT and remove its definition
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>