hv: Add initialize pm.c

Now, we only add native msr save/restore functions. The native power
related functions will be put to this file.

Signed-off-by: Zheng Gen <gen.zheng@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/pm.c

@@ -0,0 +1,14 @@
+/*
+ * Copyright (C) <2018> Intel Corporation
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include <hypervisor.h>
+
+void restore_msrs(void)
+{
+#ifdef STACK_PROTECTOR
+	struct stack_canary *psc = &get_cpu_var(stack_canary);
+
+	msr_write(MSR_IA32_FS_BASE, (uint64_t)psc);
+#endif
+}