Add a "Performance tuning" section to the network driver guide covering the
knobs that matter most for throughput on Wi-Fi lower-half drivers whose MAC
runs on a companion core: RX quota as backpressure, keeping the RX thread
priority at or below the vendor packet-delivery task, and capping the TCP
window / send buffer (backed by the shared IOB pool) on lossy wireless paths.
Signed-off-by: raul_chen <raul_chen@realsil.com.cn>
Upperhalf supports multiple working modes at the same time,
which is specified by NIC when register
Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>