[wpa_supplicant] Cherry-pick security fixes (April 29, 2019)

09ab81b9e WPA: Clear authenticator keys for a STA on deinit/disconnection
7958223fd EAP-pwd: Use const_time_memcmp() for pwd_value >= prime comparison
8e14b030e SAE: Use const_time_memcmp() for pwd_value >= prime comparison
c3805fb62 Ignore channel switch event if AP interface is not yet ready
eb314e8af Verify that channel info is available in hostapd_hw_get_channel()
b9058266f Clear cached extended_capa pointers on hapd_deinit() call

Bug: 129344244
Test: Connect to SAE network
Test: Connect to EAP network
Test: Enable/disable SoftAP
Test: Regression test (Bug: 131703857)
Change-Id: Iac0d8a7972b905da0d0f0f7414f1eea910b8986b
6 files changed