chore: format code and fix build error

src/dev/sdl/lv_sdl_window.c

@@ -15,6 +15,10 @@
 #define SDL_MAIN_HANDLED /*To fix SDL's "undefined reference to WinMain" issue*/
 #include LV_SDL_INCLUDE_PATH
 
+#if LV_USE_DRAW_SDL
+    #include <SDL2/SDL_image.h>
+#endif
+
 /*********************
  *      DEFINES
  *********************/
@@ -75,10 +79,12 @@ lv_display_t * lv_sdl_window_create(int32_t hor_res, int32_t ver_res)
         event_handler_timer = lv_timer_create(sdl_event_handler, 5, NULL);
         lv_tick_set_cb(SDL_GetTicks);
 
+#if LV_USE_DRAW_SDL
         if(!(IMG_Init(IMG_INIT_PNG) & IMG_INIT_PNG)) {
             fprintf(stderr, "could not initialize sdl2_image: %s\n", IMG_GetError());
             return NULL;
         }
+#endif
 
         inited = true;
     }

src/libs/libjpeg_turbo/lv_libjpeg_turbo.c

@@ -475,12 +475,10 @@ static void error_exit(j_common_ptr cinfo)
     longjmp(myerr->jb, 1);
 }
 
-
 static void cache_invalidate_cb(lv_cache_entry_t * entry)
 {
     if(entry->src_type == LV_CACHE_SRC_TYPE_PATH) lv_free((void *)entry->src);
     lv_free((void *)entry->data);
 }
 
-
 #endif /*LV_USE_LIBJPEG_TURBO*/

src/libs/libpng/lv_libpng.c

@@ -301,7 +301,6 @@ static const void * decode_png_file(const char * filename)
     return image_data;
 }
 
-
 static void cache_invalidate_cb(lv_cache_entry_t * entry)
 {
     lv_free((void *)entry->src);

src/libs/tiny_ttf/lv_tiny_ttf.c

@@ -126,7 +126,6 @@ static void cache_invalidate_cb(lv_cache_entry_t * entry)
     lv_draw_buf_free((void *)entry->data);
 }
 
-
 static const uint8_t * ttf_get_glyph_bitmap_cb(const lv_font_t * font, uint32_t unicode_letter, uint8_t * bitmap_buf)
 {
     LV_UNUSED(bitmap_buf);
@@ -288,5 +287,4 @@ void lv_tiny_ttf_destroy(lv_font_t * font)
     }
 }
 
-
 #endif