mmc: omap_hsmmc: Pin remux workaround to support SDIO interrupt on AM335x

The am335x can't detect pending cirq in PM runtime suspend.
This patch reconfigures dat1 as a GPIO before going to suspend.
SDIO interrupts are detected with the GPIO, the GPIO will only wake
the module from suspend, SDIO irq detection will still happen through the
IP block.

Idea of remuxing the pins by Tony Lindgren. Code contributions from
Tony Lindgren and Balaji T K <balajitk@ti.com>

Signed-off-by: Andreas Fenkart <afenkart@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Balaji T K <balajitk@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>