Add v4-tft code.

variants/heltec_v4/target.h

@@ -9,7 +9,11 @@
 #include <helpers/SensorManager.h>
 #include <helpers/sensors/EnvironmentSensorManager.h>
 #ifdef DISPLAY_CLASS
-  #include <helpers/ui/SSD1306Display.h>
+#ifdef HELTEC_LORA_V4_OLED
+    #include <helpers/ui/SSD1306Display.h>
+#elif defined(HELTEC_LORA_V4_TFT)
+    #include <helpers/ui/ST7789LCDDisplay.h>
+#endif
   #include <helpers/ui/MomentaryButton.h>
 #endif