sh: sh7366 Enable SDIO IRQs

This patch enables interrupt generation for SDIO IRQs
of the SDHI block on the sh7366 processor. Use together
with a recent SDHI driver using TMIO_MMC_SDIO_IRQ and
with the MMC_CAP_SDIO_IRQ flag in the board code.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>