delete PSRAM.

boards/heltec_tracker_v2.json

@@ -6,7 +6,6 @@
       },
     "core": "esp32",
     "extra_flags": [
-      "-DBOARD_HAS_PSRAM",
       "-DARDUINO_USB_CDC_ON_BOOT=1",
       "-DARDUINO_USB_MODE=0",
       "-DARDUINO_RUNNING_CORE=1",