riscv64: Fill in some missing CPU defines, advance build further

Change-Id: Id050fad59ede444f2eab7eca681c6ec44612aaf9
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3160
Reviewed-by: Alex von Gluck IV <[email protected]>
Reviewed-by: François Revol <[email protected]>

headers/private/kernel/boot/arch/riscv64/arch_cpu.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2013-2020 Haiku, Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef BOOT_ARCH_CPU_H
+#define BOOT_ARCH_CPU_H
+
+
+#include <SupportDefs.h>
+#include <boot/vfs.h>
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+status_t boot_arch_cpu_init(void);
+void arch_ucode_load(BootVolume& volume);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif /* BOOT_ARCH_CPU_H */