MIPS: alchemy: Use irq_set_chip_handler_name_locked()

Hand in irq_data and avoid the redundant lookup of irq_desc.

Originally-from: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10700/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>