pinctrl: qcom: Don't clear status bit on irq_unmask

Clearing the status bit on irq_unmask will discard any pending interrupt
that did arrive after the irq_ack, i.e. while the IRQ handler function
was executing.

Fixes: f365be09

 ("pinctrl: Add Qualcomm TLMM driver")
Cc: stable@vger.kernel.org
Cc: Stephen Boyd <sboyd@codeaurora.org>
Reported-by: Timur Tabi <timur@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>