mmc: omap: remove unused struct component card_detect_irq

I have not found any user for this struct component.

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Link: https://lore.kernel.org/r/b6f2168b863e4273c6bca5a22fbd4a3a8ddf68d6.1608714110.git.hns@goldelico.com


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