mmc: core: Exclude unnecessary header file

From the 4.19 kernel, thread related code has been removed in queue.c.
So we can exclude unnecessary header file.

Signed-off-by: ChanWoo Lee <cw9316.lee@samsung.com>
Acked-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210125064355.28545-1-cw9316.lee@samsung.com


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