[at_socket] support alloc socket dynamically with at device#3755

Merged

BernardXiong merged 2 commits intoRT-Thread:masterfrom

luhuadong:develop

Jul 27, 2020

Commits on Jul 20, 2020

[at_socket] support alloc socket dynamically with at device
luhuadong
committed

Commits on Jul 22, 2020

[at_socket] update AT_SW_VERSION and adjust at_socket_ops
luhuadong
committed