glsl: remove ir_state_slot::swizzle

Same story as with the NIR counterpart in the previous commit.

Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22620>

src/compiler/glsl/builtin_variables.cpp

@@ -683,7 +683,6 @@ builtin_variable_generator::add_uniform(const glsl_type *type,
 	 if (type->is_array())
             slots->tokens[1] = a;
 
-	 slots->swizzle = element->swizzle;
 	 slots++;
       }
    }