memstick: fix a double-free bug in memstick_check

kfree(host->card) has been called in put_device so that
another kfree would raise cause a double-free bug.

Fixes: 0193383a ("memstick: core: fix device_register() error handling")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Link: https://lore.kernel.org/r/20201120074846.31322-1-miaoqinglang@huawei.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>