mmc: tmio/sdhi: break out interrupt request/free

Move request_irq()/free_irq() from the shared code
in tmio_mmc.c into the SDHI/tmio specific portion
in sh_mobile_sdhi.c and tmio_mmc_pio.c.

This is ground work to allow us to adjust the SDHI
code with IRQ flags and number of interupt sources.

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>