update rtos to 1.8.0

Author: bigdinotech

platform.txt

@@ -95,7 +95,7 @@ recipe.size.regex=^(?:text|ctors|rodata|datas)\s+([0-9]+).*
 tools.arduino101load.ble.fw.string="ATP1BLE00R-1631C4439"
 tools.arduino101load.ble.fw.position=169984
 # Dummy RTOS walues - don't update RTOS if not strictly needed
-tools.arduino101load.rtos.fw.string="firmware_1.6.0_arduino101"
+tools.arduino101load.rtos.fw.string="firmware_1.8.0_arduino101"
 tools.arduino101load.rtos.fw.position=147424
 #not ideal - should be inherited by the platform
 tools.arduino101load.version=2.1.0