pinctrl: qcom: Clear status bit on irq_unmask

The gpio interrupt status bit is getting set after the
irq is disabled and causing an immediate interrupt after
enablling the irq, so clear status bit on irq_unmask.

Change-Id: I89245b90b06b37671369e59c15fb24a991cc114a
Signed-off-by: Tengfei Fan <tengfeif@codeaurora.org>