ASoC: wcd-irq: correct identifier name to fix compile error

The two arguments in functions wcd_request_irq, wcd_free_irq,
wcd_enable_irq and wcd_disable_irq have same identifier names.
Correct wcd_irq_info identifier name to fix compile error

Change-Id: I6f240d3af1cd253336d070d0f3228eae96a4fcb6
Signed-off-by: Meng Wang <mengw@codeaurora.org>