mmc: tmio: Remove redundant check of mmc->slot.cd_irq

mmc: tmio: Remove redundant check of mmc->slot.cd_irq

To validate whether native hotplug needs to be used, the tmio driver checks
whether the mmc->slot.cd_irq has been successfully assigned.

This check is redundant at its current place in tmio_mmc_host_probe(), as
the mmc core assigns mmc->slot.cd_irq a valid value first when
mmc_gpiod_request_cd_irq() is called. Therefore, let's just remove the
check for now, as that also removes a layering violation of the tmio driver
accessing core specific data via ->slot.cd_irq.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>