esp_wifi: Always connect Station in PMF mode if possible

While using esp_wifi_set_config, flag pmf_capable defaults to 0.
Users may not bother to enable it, which prevents connection to a
WPA3 AP. Or the AP may reset into WPA3 mode failing the re-connection.
To ensure better security, deprecate the pmf_capable flag and set it to
true internally.

examples/wifi/getting_started/station/main/station_example_main.c

@@ -96,11 +96,6 @@ void wifi_init_sta(void)
              * However these modes are deprecated and not advisable to be used. Incase your Access point
              * doesn't support WPA2, these mode can be enabled by commenting below line */
 	     .threshold.authmode = WIFI_AUTH_WPA2_PSK,
-
-            .pmf_cfg = {
-                .capable = true,
-                .required = false
-            },
         },
     };
     ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA) );

examples/wifi/iperf/main/cmd_wifi.c

@@ -161,7 +161,6 @@ static bool wifi_cmd_sta_join(const char *ssid, const char *pass)
     int bits = xEventGroupWaitBits(wifi_event_group, CONNECTED_BIT, 0, 1, 0);
 
     wifi_config_t wifi_config = { 0 };
-    wifi_config.sta.pmf_cfg.capable = true;
 
     strlcpy((char *) wifi_config.sta.ssid, ssid, sizeof(wifi_config.sta.ssid));
     if (pass) {

examples/wifi/wifi_eap_fast/main/wifi_eap_fast_main.c

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: CC0-1.0
  */
@@ -89,12 +89,6 @@ static void initialise_wifi(void)
     wifi_config_t wifi_config = {
         .sta = {
             .ssid = EXAMPLE_WIFI_SSID,
-#if defined(CONFIG_EXAMPLE_WPA3_ENTERPRISE)
-            .pmf_cfg = {
-                .capable = true,
-                .required = false
-            },
-#endif
         },
     };
     ESP_LOGI(TAG, "Setting WiFi configuration SSID %s...", wifi_config.sta.ssid);

examples/wifi/wifi_enterprise/main/wifi_enterprise_main.c

@@ -122,15 +122,8 @@ static void initialise_wifi(void)
     wifi_config_t wifi_config = {
         .sta = {
             .ssid = EXAMPLE_WIFI_SSID,
-#if defined(CONFIG_EXAMPLE_WPA3_ENTERPRISE)
-            .pmf_cfg = {
-                .capable = true,
-                .required = false
-            },
-#endif
 #if defined (CONFIG_EXAMPLE_WPA3_192BIT_ENTERPRISE)
             .pmf_cfg = {
-                .capable = true,
                 .required = true
             },
 #endif