Prevent SKR Pro bootloader corruption (#17657)

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

buildroot/share/PlatformIO/boards/BigTree_Btt002.json

@@ -37,6 +37,7 @@
       "dfu",
       "jlink"
     ],
+    "offset_address": "0x8008000",
     "require_upload_port": true,
     "use_1200bps_touch": false,
     "wait_for_upload_port": false

buildroot/share/PlatformIO/boards/BigTree_SKR_Pro.json

@@ -37,6 +37,7 @@
       "dfu",
       "jlink"
     ],
+    "offset_address": "0x8008000",
     "require_upload_port": true,
     "use_1200bps_touch": false,
     "wait_for_upload_port": false