Unified sysroot: arch-X/include directories are gone.

Bug: N/A
Test: builds
Change-Id: I98fc6a1a3c0be1c90b1deb35b54f36ab16a202ac
diff --git a/cc/config/x86_64_device.go b/cc/config/x86_64_device.go
index 2a6fe2a..a98001e 100644
--- a/cc/config/x86_64_device.go
+++ b/cc/config/x86_64_device.go
@@ -159,7 +159,7 @@
 	pctx.StaticVariable("X86_64Cflags", strings.Join(x86_64Cflags, " "))
 	pctx.StaticVariable("X86_64Ldflags", strings.Join(x86_64Ldflags, " "))
 	pctx.StaticVariable("X86_64Cppflags", strings.Join(x86_64Cppflags, " "))
-	pctx.StaticVariable("X86_64IncludeFlags", bionicHeaders("x86_64", "x86"))
+	pctx.StaticVariable("X86_64IncludeFlags", bionicHeaders("x86"))
 
 	// Clang cflags
 	pctx.StaticVariable("X86_64ClangCflags", strings.Join(ClangFilterUnknownCflags(x86_64Cflags), " "))