build.rs: Add include path for rpc_caller_session.h

The new trusted services RPC calls come from rpc_caller_session.h.
Include this while generating bindings using bindgen.

Signed-off-by: Gowtham Suresh Kumar <gowtham.sureshkumar@arm.com>

build.rs

@@ -19,6 +19,7 @@ fn generate_ts_bindings(ts_include_dir: String) -> Result<()> {
     println!("cargo:rerun-if-changed={}", header);
 
     let bindings = bindgen::Builder::default()
+        .clang_arg(format!("-I{}", ts_include_dir))
         .clang_arg(format!(
             "-I{}",
             ts_include_dir + "/components/rpc/common/interface"