Add WIFI_ variables into soong config

To migrate libwifi-hal module from make to soong, WIFI_ make variables
are added to soong config variables in `wifi` namespace.

Bug: 239984067
Test: m libwifi-hal
Merged-In: If60f5909619af887be8e0086a8dfef65dc97cce0
Change-Id: If60f5909619af887be8e0086a8dfef65dc97cce0
(cherry picked from commit 4abb3d43b4baf74cf7b17fee380d5b4c77a2bc9d)
diff --git a/core/soong_config.mk b/core/soong_config.mk
index c4a40af..e975d8a 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -250,7 +250,7 @@
 $(foreach namespace,$(SOONG_CONFIG_NAMESPACES),\
   $(call add_json_map, $(namespace))\
   $(foreach key,$(SOONG_CONFIG_$(namespace)),\
-    $(call add_json_str,$(key),$(SOONG_CONFIG_$(namespace)_$(key))))\
+    $(call add_json_str,$(key),$(subst ",\",$(SOONG_CONFIG_$(namespace)_$(key)))))\
   $(call end_json_map))
 $(call end_json_map)