vulkan: SDL_Vulkan_CreateSurface now returns the usual int (0=ok, -1=error).

Fixes #10091.

test/testffmpeg_vulkan.c

@@ -253,10 +253,7 @@ static int createInstance(VulkanVideoContext *context)
 
 static int createSurface(VulkanVideoContext *context, SDL_Window *window)
 {
-    if (!SDL_Vulkan_CreateSurface(window,
-                                  context->instance,
-                                  NULL,
-                                  &context->surface)) {
+    if (SDL_Vulkan_CreateSurface(window, context->instance, NULL, &context->surface) < 0) {
         context->surface = VK_NULL_HANDLE;
         return -1;
     }