pinctrl: exynos: remove duplicate calls in irq handler

Because chained_irq_enter() has already called chip->irq_mask() and
chip->irq_ack(), also chained_irq_exit() will call chip->irq_unmask(),
so it's not necessary to call chip->irq_*() here.

Signed-off-by: Perr Zhang <strongbox8@zoho.com>
Acked-by: Tomasz Figa <tomasz.figa@gmail.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
[Hand-edited from whitespace damaged patch]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>