This patch enables the interrupt generation for SDIO IRQs
of the sdhi controllers of the SoC. To make sure interrupt
are handled announce the MMC_CAP_SDIO_IRQ capability
on ecovec, kfr2r09 and se7724.

Tested with a b43-based SDIO wireless card on ecovec.
Signed-off-by: NArnd Hannemann <arnd@arndnet.de>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>