add builtin STM32 DMA2D support

src/lv_conf_internal.h

@@ -263,6 +263,12 @@
 #ifndef LV_USE_GPU
 #define LV_USE_GPU              1
 #endif
+#ifndef LV_GPU_INCLUDE
+#define LV_GPU_INCLUDE  <stdint.h> /*E.g. "stm32f7xx_hal.h"*/
+#endif
+#ifndef LV_USE_GPU_STM32_DMA2D
+#define LV_USE_GPU_STM32_DMA2D  1
+#endif
 
 /* 1: Enable file system (might be required for images */
 #ifndef LV_USE_FILESYSTEM