media: mtk-vpu: Drop unnecessary call to platform_get_resource()
mtk_vpu_probe() calls platform_get_resource(pdev, IORESOURCE_IRQ, ..)
to check if IRQ resource exists and later calls
platform_get_irq(pdev, ..) to get the actual IRQ.
This patch drops an unnecessary call to platform_get_resource() and
checks the return value of platform_get_irq(pdev, ..) to make sure the
IRQ line is valid.