anv: enable graphics pipeline libraries by default

Since we are disabling mesh, which has issues with gpl, enable gpl by
default now, leaving the renamed environment variable as a way to
disable it for debug purposes.

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22910>

src/intel/vulkan/anv_private.h

@@ -865,7 +865,6 @@ struct anv_physical_device {
     struct intel_device_info                      info;
 
     bool                                        video_decode_enabled;
-    bool                                        gpl_enabled;
 
     struct brw_compiler *                       compiler;
     struct isl_device                           isl_dev;