hwcontext_vulkan: ask for storage images by default

The issue is that we ask for storage images by default if
available, but because that is gated by the format supporting
storage images, and the check for the format supporting storage
images is gated by the usage, this resulted in a catch-22.

libavutil/hwcontext_vulkan.c

@@ -2617,7 +2617,8 @@ static int vulkan_frames_init(AVHWFramesContext *hwfc)
         err = vkfmt_from_pixfmt2(hwfc->device_ctx, hwfc->sw_format,
                                  hwctx->tiling, NULL,
                                  NULL, NULL, &supported_usage, 0,
-                                 hwctx->usage & VK_IMAGE_USAGE_STORAGE_BIT);
+                                 !hwctx->usage ||
+                                 (hwctx->usage & VK_IMAGE_USAGE_STORAGE_BIT));
         if (err < 0) {
             av_log(hwfc, AV_LOG_ERROR, "Unsupported sw format: %s!\n",
                    av_get_pix_fmt_name(hwfc->sw_format));
@@ -2628,7 +2629,8 @@ static int vulkan_frames_init(AVHWFramesContext *hwfc)
                                  hwctx->tiling, hwctx->format, NULL,
                                  NULL, &supported_usage,
                                  disable_multiplane,
-                                 hwctx->usage & VK_IMAGE_USAGE_STORAGE_BIT);
+                                 !hwctx->usage ||
+                                 (hwctx->usage & VK_IMAGE_USAGE_STORAGE_BIT));
         if (err < 0)
             return err;
     }