mmc: wmt-sdmmc: Remove deprecated IRQF_DISABLED

It's a NOOP since 2.6.35 and it will be removed one day.
This is not trivial because current code uses hard coded 32 instead of
IRQF_DISABLED in the request_irq call.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>