hv: refactor seed management

New component to maintain seed retrieval and derivation: seed.

1. Retrieve seed from bootloader in Hypervisor's boot stage.
2. Derive virtual seed for Guest/Trusty if need.

Tracked-On: #2724
Signed-off-by: Qi Yadong <yadong.qi@intel.com>
Reviewed-by: Zhu Bing <bing.zhu@intel.com>

hypervisor/arch/x86/seed/seed_abl.h

@@ -0,0 +1,12 @@
+/*
+ * Copyright (C) 2018 Intel Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SEED_ABL_H_
+#define SEED_ABL_H_
+
+bool parse_seed_abl(uint64_t addr, struct physical_seed *phy_seed);
+
+#endif /* SEED_ABL_H_ */