wifi: Fix linking of WiFi functions dependent on PM_ENABLE

The following functions are only defined when CONFIG_PM_ENABLE is defined:

- wifi_apb80m_request()
- wifi_apb80m_release()

This commit makes their linker script mapping statements also dependent on CONFIG_PM_ENABLE
thus fixing some linker errors when CONFIG_PM_ENABLE is disabled.

components/esp_wifi/linker.lf

@@ -147,8 +147,9 @@ entries:
     if ESP_WIFI_SLP_IRAM_OPT =y:
         esp_adapter:wifi_clock_enable_wrapper (noflash)
         esp_adapter:wifi_clock_disable_wrapper (noflash)
-        wifi_init:wifi_apb80m_request (noflash)
-        wifi_init:wifi_apb80m_release (noflash)
+        if PM_ENABLE = y:
+            wifi_init:wifi_apb80m_request (noflash)
+            wifi_init:wifi_apb80m_release (noflash)
 
 [mapping:esp_timer_wifi_pm]
 archive: libesp_timer.a