KVM: Move vm_list kvm_lock declarations out of x86

The variables vm_list and kvm_lock are common to all architectures, so
move the declarations from arch/x86/include/asm/kvm_host.h to
include/linux/kvm_host.h.

Fixes sparse warnings like these when building for arm64:

  virt/kvm/kvm_main.c: warning: symbol 'kvm_lock' was not declared. Should it be static?
  virt/kvm/kvm_main.c: warning: symbol 'vm_list' was not declared. Should it be static?
Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -94,9 +94,6 @@
 
 #define ASYNC_PF_PER_VCPU 64
 
-extern raw_spinlock_t kvm_lock;
-extern struct list_head vm_list;
-
 struct kvm_vcpu;
 struct kvm;
 struct kvm_async_pf;

include/linux/kvm_host.h

@@ -135,6 +135,9 @@ struct kvm;
 struct kvm_vcpu;
 extern struct kmem_cache *kvm_vcpu_cache;
 
+extern raw_spinlock_t kvm_lock;
+extern struct list_head vm_list;
+
 struct kvm_io_range {
 	gpa_t addr;
 	int len;