nimble/host: Remove redundant check in connection latency
nimble/host: Remove redundant check in connection latency

* The `params->latency` is uint16_t and BLE_HCI_CONN_LATENCY_MIN is 0 which is
  why we can drop it.

apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble