xen/x86: remove duplicated include from enlighten.c

Remove duplicated include.

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)

CC: stable@vger.kernel.org
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/xen/enlighten.c

@@ -81,8 +81,6 @@
 #include "smp.h"
 #include "multicalls.h"
 
-#include <xen/events.h>
-
 EXPORT_SYMBOL_GPL(hypercall_page);
 
 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);