nir: add a new access flag to allow access in helper invocations

v2: Add nir_print support

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13718>

src/compiler/shader_enums.h

@@ -903,6 +903,9 @@ enum gl_access_qualifier
 
    /** Use as little cache space as possible. */
    ACCESS_STREAM_CACHE_POLICY = (1 << 7),
+
+   /** Execute instruction also in helpers. */
+   ACCESS_INCLUDE_HELPERS = (1 << 8),
 };
 
 /**