SDL: kmsdrm: Explicitly set the surface transform and alpha mode

SDL Commits
1 
From d6641d7123a48fa7b644f81441f561ba0372f77f Mon Sep 17 00:00:00 2001
From: Niklas Haas <[EMAIL REDACTED]>
Date: Mon, 19 Jul 2021 11:52:57 +0200
Subject: [PATCH] kmsdrm: Explicitly set the surface transform and alpha mode

This is required by the specification. Set these to sensible defaults.
Fixes a validation layer error that occurs otherwise.
---
 src/video/kmsdrm/SDL_kmsdrmvulkan.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/video/kmsdrm/SDL_kmsdrmvulkan.c b/src/video/kmsdrm/SDL_kmsdrmvulkan.c
index b08a41e78..3b80ac566 100644
--- a/src/video/kmsdrm/SDL_kmsdrmvulkan.c
+++ b/src/video/kmsdrm/SDL_kmsdrmvulkan.c
@@ -427,6 +427,8 @@ SDL_bool KMSDRM_Vulkan_CreateSurface(_THIS,
     /* For now, simply use the first plane. */
     display_plane_surface_create_info.planeIndex = 0;
     display_plane_surface_create_info.imageExtent = image_size;
+    display_plane_surface_create_info.transform = VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR;
+    display_plane_surface_create_info.alphaMode = VK_DISPLAY_PLANE_ALPHA_OPAQUE_BIT_KHR;
     result = vkCreateDisplayPlaneSurfaceKHR(instance,
                                      &display_plane_surface_create_info,
                                      NULL,