mmc: tmio_mmc: do not enable card hotplug interrupts, if unused

If TMIO MMC is used in polling mode, or the card is non-removable, or
card-detection is performed, using an external interrupt, there is no
need to enable controller native card hotplug interrupts.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>