KVM: Remove redundant alloc_vmcs_cpu declaration

alloc_vmcs_cpu is already declared (static) above, no need to
redeclare.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/vmx.c

@@ -949,8 +949,6 @@ static void free_kvm_area(void)
 		free_vmcs(per_cpu(vmxarea, cpu));
 }
 
-extern struct vmcs *alloc_vmcs_cpu(int cpu);
-
 static __init int alloc_kvm_area(void)
 {
 	int cpu;