memstick: Skip allocating card when removing host

After commit 6827ca57 ("memstick: rtsx_usb_ms: Support runtime power
management"), removing module rtsx_usb_ms will be stuck.

The deadlock is caused by powering on and powering off at the same time,
the former one is when memstick_check() is flushed, and the later is called
by memstick_remove_host().

Soe let's skip allocating card to prevent this issue.

Fixes: 6827ca57 ("memstick: rtsx_usb_ms: Support runtime power management")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20200925084952.13220-1-kai.heng.feng@canonical.com


Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>