platform_get_irq() returns -ERRNO on error.  In such case comparison
to 0 would pass the check.

Fixes: 179c02fe ("drm/tve200: Add new driver for TVE200")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200827071107.27429-2-krzk@kernel.org