Prepares hostapd for use by a wifi HAL vendor APEX

- Allows hostapd AIDL to read from an APEX for config files.
- Creates a cc_defaults with soong config vars for hostapd that
  customized implementations can override.
- Change -DCONFIG_HIDL to -DCONFIG_AIDL

Bug: 205065320
Test: m -j with mac80211_hwsim vendor APEX on Cuttlefish
Test: Connect to wifi and run hotspot
Change-Id: Id9937724a397d74c070a0b176c5ec0c18b71c9d1
diff --git a/wpa_supplicant/Android.bp b/wpa_supplicant/Android.bp
index eefce6e..a5cb2bb 100644
--- a/wpa_supplicant/Android.bp
+++ b/wpa_supplicant/Android.bp
@@ -135,7 +135,7 @@
         "-DCONFIG_FILS",
         "-DCONFIG_GAS",
         "-DCONFIG_GAS_SERVER",
-        "-DCONFIG_HIDL",
+        "-DCONFIG_AIDL",
         "-DCONFIG_HMAC_SHA256_KDF",
         "-DCONFIG_HMAC_SHA384_KDF",
         "-DCONFIG_HMAC_SHA512_KDF",