power: reset: gemini-poweroff: Fix IRQ check in gemini_poweroff_probe

power: reset: gemini-poweroff: Fix IRQ check in gemini_poweroff_probe

platform_get_irq() returns negative error number instead 0 on failure.
And the doc of platform_get_irq() provides a usage example:

    int irq = platform_get_irq(pdev, 0);
    if (irq < 0)
        return irq;

Fix the check of return value to catch errors correctly.

Fixes: a32d0f5b9818 ("power: reset: Add a driver for the Gemini poweroff")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>