kvm: Move kvmclock into hw/kvm folder

More KVM-specific devices will come, so let's start with moving the
kvmclock into a dedicated folder.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

hw/kvm/clock.h

@@ -0,0 +1,24 @@
+/*
+ * QEMU KVM support, paravirtual clock device
+ *
+ * Copyright (C) 2011 Siemens AG
+ *
+ * Authors:
+ *  Jan Kiszka        <jan.kiszka@siemens.com>
+ *
+ * This work is licensed under the terms of the GNU GPL version 2.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#ifdef CONFIG_KVM
+
+void kvmclock_create(void);
+
+#else /* CONFIG_KVM */
+
+static inline void kvmclock_create(void)
+{
+}
+
+#endif /* !CONFIG_KVM */