Use updated xtensa toolchain for Arduino framework

Author: ivankravets

platform.json

@@ -41,7 +41,7 @@
   "packages": {
     "toolchain-xtensa": {
       "type": "toolchain",
-      "version": "~1.40802.0"
+      "version": "<3"
     },
     "framework-arduinoespressif8266": {
       "type": "framework",

platform.py

@@ -19,6 +19,8 @@ class Espressif8266Platform(PlatformBase):
 
     def configure_default_packages(self, variables, targets):
         framework = variables.get("pioframework")
+        if "arduino" not in framework:
+            self.packages['tool-mkspiffs']['optional'] = "~1.40802.0"
         if "buildfs" in targets:
             self.packages['tool-mkspiffs']['optional'] = False
         return PlatformBase.configure_default_packages(