KVM: stats: remove dead stores

These stores are copied and pasted from the "if" statements above.
They are dead and while they are not really a bug, they can be
confusing to anyone reading the code as well.  Remove them.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/binary_stats.c

@@ -136,9 +136,7 @@ ssize_t kvm_stats_read(char *id, const struct kvm_stats_header *header,
 		src = stats + pos - header->data_offset;
 		if (copy_to_user(dest, src, copylen))
 			return -EFAULT;
-		remain -= copylen;
 		pos += copylen;
-		dest += copylen;
 	}
 
 	*offset = pos;