Added GPU init to lv_init

Changed blend buffer attr to more general LV_DMA_ATTR
Added define for CMSIS header
Fixed bug with turning on peripheral clock

src/lv_gpu/lv_gpu_stm32_dma2d.c

@@ -11,7 +11,7 @@
 
 #if LV_USE_GPU_STM32_DMA2D
 
-#include "stm32f429xx.h"
+#include LV_CPU_DMA2D_CMSIS_INCLUDE
 
 /*********************
  *      DEFINES
@@ -64,6 +64,9 @@ void lv_gpu_stm32_dma2d_init(void)
     /* Enable DMA2D clock */
     RCC->AHB1ENR |= RCC_AHB1ENR_DMA2DEN;
 
+    /* Delay after setting peripheral clock */
+    volatile uint32_t temp = RCC->AHB1ENR;
+
     /* set output colour mode */
     DMA2D->OPFCCR = DMA2D_COLOR_FORMAT;
 }