Fix flash size for BlynkBoard

Author: ivankravets

boards/sparkfunBlynk.json

@@ -15,7 +15,7 @@
   "name": "SparkFun Blynk Board",
   "upload": {
     "maximum_ram_size": 81920,
-    "maximum_size": 1044464,
+    "maximum_size": 4194304,
     "require_upload_port": true,
     "resetmethod": "nodemcu",
     "speed": 115200