Revert "Remove range command"

This reverts commit c58d845339.

src/drivers/sf0x/sf0x.cpp

@@ -494,10 +494,6 @@ SF0X::measure()
 	/*
 	 * Send the command to begin a measurement.
 	 */
-
-	// XXX we probably should not try to talk to the sensor
-	// it seems to mind UART traffic.
-	#if 0
 	char cmd = SF0X_TAKE_RANGE_REG;
 	ret = ::write(_fd, &cmd, 1);
 
@@ -506,7 +502,6 @@ SF0X::measure()
 		log("write fail %d", ret);
 		return ret;
 	}
-	#endif
 
 	ret = OK;