compiler/spirv: Handle the LocalSizeHint execution modes

It's basically the same as the LocalSize version except it fills
the local_size_hint array.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7565>

src/compiler/shader_info.h

@@ -347,6 +347,7 @@ typedef struct shader_info {
 
       struct {
          uint16_t local_size[3];
+         uint16_t local_size_hint[3];
 
          bool local_size_variable:1;
          uint8_t user_data_components_amd:3;