KVM: Remove stat_set from debugfs

We shouldn't define stat_set on the debug attributes, since that will
cause silent failure on writing: without a set argument, userspace
will get -EACCESS.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/kvm_main.c

@@ -3017,11 +3017,7 @@ static u64 stat_get(void *_offset)
 	return total;
 }
 
-static void stat_set(void *offset, u64 val)
-{
-}
-
-DEFINE_SIMPLE_ATTRIBUTE(stat_fops, stat_get, stat_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(stat_fops, stat_get, NULL, "%llu\n");
 
 static __init void kvm_init_debug(void)
 {