vulkan: Swapped out a free() that should have been an SDL_free().

Fixes (for real this time!) the Visual Studio builds.

src/video/SDL_vulkan_utils.c

@@ -301,7 +301,7 @@ SDL_bool SDL_Vulkan_Display_CreateSurface(void *vkGetInstanceProcAddr_,
         SDL_LogDebug(SDL_LOG_CATEGORY_VIDEO, "vulkandisplay: Display: %s Native resolution: %ux%u",
                 displayProperties[displayId].displayName, extent.width, extent.height);
 
-        free(displayProperties);
+        SDL_free(displayProperties);
         displayProperties = NULL;
 
         /* Get display mode properties for the chosen display */