Remove Export_static_lib_headers from codegen

It is not necessary to export headers from static libraries included
using whole_static_libs as that automatically exports the headers.

Test: m checkbuild
Bug: 134379140
Change-Id: Iea85dedf91f404739d12b3a7971cd87c02e1ab6d
Exempt-From-Owner-Approval: needed to fix build failure
diff --git a/build/codegen.go b/build/codegen.go
index aa942a7..f407e5d 100644
--- a/build/codegen.go
+++ b/build/codegen.go
@@ -114,8 +114,7 @@
 
 type CodegenLibraryArchProperties struct {
 	Static struct {
-		Whole_static_libs         []string
-		Export_static_lib_headers []string
+		Whole_static_libs []string
 	}
 	Shared struct {
 		Shared_libs               []string