Unify FYSETC F6 1.3 / 1.4 (#20507)

Co-authored-by: Scott Lahteine <github@thinkyhead.com>

buildroot/share/PlatformIO/boards/fysetc_f6.json

@@ -0,0 +1,34 @@
+{
+  "build": {
+    "core": "arduino",
+    "extra_flags": "-DARDUINO_AVR_MEGA2560",
+    "f_cpu": "16000000L",
+    "hwids": [
+      [
+        "0x27b2",
+        "0x0002"
+      ]
+    ],
+    "mcu": "atmega2560",
+    "variant": "fysetcf6"
+  },
+  "debug": {
+    "simavr_target": "atmega2560",
+    "avr-stub": {
+      "speed": 115200
+    }
+  },
+  "frameworks": [
+    "arduino"
+  ],
+  "name": "FYSETC F6",
+  "upload": {
+    "maximum_ram_size": 8192,
+    "maximum_size": 258048,
+    "protocol": "wiring",
+    "require_upload_port": true,
+    "speed": 115200
+  },
+  "url": "https://www.fysetc.com/",
+  "vendor": "FYSETC"
+}