asahi: Fix tools=all builds

don't need clc here.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26017>

src/asahi/meson.build

@@ -6,10 +6,12 @@ inc_asahi = include_directories([
    '.', 'layout', 'lib', 'compiler'
 ])
 
-subdir('layout')
-subdir('clc')
-subdir('lib')
-subdir('compiler')
+if with_gallium_asahi
+   subdir('layout')
+   subdir('clc')
+   subdir('lib')
+   subdir('compiler')
+endif
 
 if with_tools.contains('drm-shim')
   subdir('drm-shim')