Copy-paste bug: 'debug' hint clamps sc->mch_rec instead of sc->dbg_level (and clamping is skipped exactly when the hint exists)

Summary

emu_pci_attach does: if (resource_int_value(...debug...&sc->dbg_level)) RANGE(sc->mch_rec, 0, 2); - the RANGE clamps the wrong variable (copy-paste from the multichannel block), and because resource_int_value returns 0 on success the clamp is only executed when the hint is ABSENT. dbg_level is never bounded from loader.conf, and the dev.emu10kx.N.debug sysctl is CTLFLAG_RW, so any local user can set it to any int. Consequences on hardware: emu_intr() prints per unhandled IRQ at dbg_level>1 - unbounded console/log flood. Log-spam DoS only. One-line fix.