feat(FF-A): create ffa_init to prefetch the SPMC ID

Prefetch the SPMC ID to prevent unnecessary SMC calls. Also group
SPMC initialization code into an arch specific initialization file.

Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
Change-Id: I0be0be95a8eea9d39eaf8b5ddc3600bcc7d66ebe
diff --git a/src/arch/aarch64/hypervisor/arch_init.c b/src/arch/aarch64/hypervisor/arch_init.c
new file mode 100644
index 0000000..bcadd60
--- /dev/null
+++ b/src/arch/aarch64/hypervisor/arch_init.c
@@ -0,0 +1,19 @@
+/*
+ * Copyright 2021 The Hafnium Authors.
+ *
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/BSD-3-Clause.
+ */
+
+#include "hf/arch/ffa.h"
+#include "hf/arch/plat/psci.h"
+
+/**
+ * Performs arch specific boot time initialization.
+ */
+void arch_one_time_init(void)
+{
+	plat_psci_init();
+	arch_ffa_init();
+}