Merge branch 'feature/add_support_for_signal_test_v3.1' into 'release/v3.1'

esp32: add support for WiFi signal test (backport v3.1)

See merge request idf/esp-idf!4754
This commit is contained in:
Jiang Jiang Jian
2019-04-15 17:45:50 +08:00