mmc: sdhi: no need for special interrupt flags

Modify the SDHI driver to get rid of unwanted irq flags.

IRQF_DISABLED unused, see include/linux/interrupt.h
IRQF_TRIGGER_FALLING only relevant on external IRQ pins,
but since SDHI is internal in the SoC this can go away.

Needed to support SDHI on sh73a0 that comes with a GIC
that errors out with the IRQF_TRIGGER_FALLING setting.

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