HID: hyperv: fix possible memory leak in mousevsc_probe()

If hid_add_device() returns error, it should call hid_destroy_device()
to free hid_dev which is allocated in hid_allocate_device().

Fixes: 74c4fb05

 ("HID: hv_mouse: Properly add the hid device")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>