SDL_kmsdrmvideo.c: move SDL_kmsdrmvulkan.h include to before all others

Fixes vulkan redefinition errors:

In file included from /tmp/SDL3/src/video/kmsdrm/.././khronos/vulkan/vulkan.h:11,
                 from /tmp/SDL3/src/video/kmsdrm/../SDL_vulkan_internal.h:52,
                 from /tmp/SDL3/src/video/kmsdrm/SDL_kmsdrmvulkan.h:32,
                 from /tmp/SDL3/src/video/kmsdrm/SDL_kmsdrmvideo.c:44:
/tmp/SDL3/src/video/kmsdrm/.././khronos/vulkan/vulkan_core.h:101: error: redefinition of typedef ‘VkInstance’
/tmp/SDL3/include/SDL3/SDL_vulkan.h:52: note: previous declaration of ‘VkInstance’ was here
In file included from /tmp/SDL3/src/video/kmsdrm/.././khronos/vulkan/vulkan.h:11,
                 from /tmp/SDL3/src/video/kmsdrm/../SDL_vulkan_internal.h:52,
                 from /tmp/SDL3/src/video/kmsdrm/SDL_kmsdrmvulkan.h:32,
                 from /tmp/SDL3/src/video/kmsdrm/SDL_kmsdrmvideo.c:44:
/tmp/SDL3/src/video/kmsdrm/.././khronos/vulkan/vulkan_core.h:7513: error: redefinition of typedef ‘VkSurfaceKHR’
/tmp/SDL3/include/SDL3/SDL_vulkan.h:53: note: previous declaration of ‘VkSurfaceKHR’ was here
make[2]: *** [CMakeFiles/SDL3-shared.dir/src/video/kmsdrm/SDL_kmsdrmvideo.c.o] Error 1

src/video/kmsdrm/SDL_kmsdrmvideo.c

@@ -23,6 +23,8 @@
 
 #ifdef SDL_VIDEO_DRIVER_KMSDRM
 
+#include "SDL_kmsdrmvulkan.h"
+
 /* SDL internals */
 #include "../../events/SDL_events_c.h"
 #include "../../events/SDL_keyboard_c.h"
@@ -41,7 +43,7 @@
 #include "SDL_kmsdrmmouse.h"
 #include "SDL_kmsdrmvideo.h"
 #include "SDL_kmsdrmopengles.h"
-#include "SDL_kmsdrmvulkan.h"
+/*#include "SDL_kmsdrmvulkan.h"*/
 #include <dirent.h>
 #include <errno.h>
 #include <poll.h>