turnip/kgsl: new flag TU_USE_KGSL

There are some cases using kgsl backend on linux that is still not usual
setup though, we need to consider too.

Regarding the timeline semaphore feature, we could implement it for
the kgsl backend in the future, and probalby it should be using the
existing code in tu_drm.

See #4738, #4907

Signed-off-by: Hyunjun Ko <zzoon@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11488>

src/freedreno/vulkan/meson.build

@@ -99,6 +99,7 @@ if with_xlib_lease
 endif
 
 if with_freedreno_kgsl
+  tu_flags += '-DTU_USE_KGSL'
   libtu_files += files('tu_kgsl.c')
 else
   libtu_files += files('tu_drm.c')

src/freedreno/vulkan/tu_device.c

@@ -149,7 +149,7 @@ get_device_extensions(const struct tu_physical_device *device,
       .KHR_swapchain = TU_HAS_SURFACE,
       .KHR_variable_pointers = true,
       .KHR_vulkan_memory_model = true,
-#ifndef ANDROID
+#ifndef TU_USE_KGSL
       .KHR_timeline_semaphore = true,
 #endif
 #ifdef VK_USE_PLATFORM_DISPLAY_KHR