doc: add build config option in hns3 guide
doc: add build config option in hns3 guide

This patch adds description of max TQP number per PF for config file
option.

Signed-off-by: Min Hu (Connor) <f02e10cb0a484c51b0f8634f83fbb4ab9ded1c6a@huawei.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk