Properly handle Super-I/O chips without logical device. Just report
that we can't support the chip yet, instead of spitting I/O errors.

---
 prog/detect/sensors-detect |    4 ++++
 1 file changed, 4 insertions(+)

--- lm_sensors-3.3.1.orig/prog/detect/sensors-detect
+++ lm_sensors-3.3.1/prog/detect/sensors-detect
@@ -3747,6 +3747,10 @@ sub probe_superio
 		print "\n    (hardware monitoring capabilities accessible via SMBus only)\n";
 		return FEAT_SMBUS;
 	}
+	if (!exists $chip->{logdev}) {
+		print "\n    (no support yet)\n";
+		return 0;
+	}
 
 	# Switch to the sensor logical device
 	outb($addrreg, $superio{logdevreg});