x86/mpparse: Remove duplicate io_apic.h include

Remove asm/io_apic.h which is included more than once.
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NWang Hai <wanghai38@huawei.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NPekka Enberg <penberg@kernel.org>
Link: https://lkml.kernel.org/r/20200819112910.7629-1-wanghai38@huawei.com

arch/x86/kernel/mpparse.c

@@ -24,7 +24,6 @@
 #include <asm/irqdomain.h>
 #include <asm/mtrr.h>
 #include <asm/mpspec.h>
-#include <asm/io_apic.h>
 #include <asm/proto.h>
 #include <asm/bios_ebda.h>
 #include <asm/e820/api.h>