drm/nouveau/mc: have single entry and exit points to the interrupt handler

	struct nouveau_mc *pmc = arg;

	const struct nouveau_mc_intr *map = pmc->intr_map;

	struct nouveau_subdev *unit;

	u32 stat, intr;

	u32 intr, stat;

	intr = stat = nv_rd32(pmc, 0x000100);

	if (intr == 0xffffffff)

		return IRQ_NONE;

	while (stat && map->stat) {

		if (stat & map->stat) {

	intr = nv_rd32(pmc, 0x000100);

	if (intr == 0xffffffff) /* likely fallen off the bus */

		intr = 0x00000000;

	if ((stat = intr) != 0) {

		while (map->stat) {

			if (intr & map->stat) {

				unit = nouveau_subdev(pmc, map->unit);

				if (unit && unit->intr)

					unit->intr(unit);

			intr &= ~map->stat;

				stat &= ~map->stat;

			}

			map++;

		}

		if (pmc->use_msi)

			nv_wr08(pmc, 0x088068, 0xff);

	if (intr) {

		if (stat)

			nv_error(pmc, "unknown intr 0x%08x\n", stat);

	}

	return stat ? IRQ_HANDLED : IRQ_NONE;

	return intr ? IRQ_HANDLED : IRQ_NONE;

}

int