mmc: omap_hsmmc: enable wakeup event for sdio OMAP4

To detect sdio irqs properly without spurious events,
OMAP4 needs IWE in CON and CTPL, CLKEXTFREE in HCTL to be set

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