drm/hisilicon/hibmc: fix irq_request()'s irq name variable is local

In the Linux kernel, the following vulnerability has been resolved: drm/hisilicon/hibmc: fix irq_request()'s irq name variable is local The local variable is passed in request_irq (), and there will be use after free problem, which will make request_irq failed. Using the global irq name instead of it to fix.