glsl: Silence "unused parameter" warnings in ast_type.cpp

glsl: Silence "unused parameter" warnings in ast_type.cpp

glsl/ast_type.cpp: In function ‘bool validate_point_mode(YYLTYPE*, _mesa_glsl_parse_state*, const ast_type_qualifier&, const ast_type_qualifier&)’:
glsl/ast_type.cpp:173:30: warning: unused parameter ‘loc’ [-Wunused-parameter]
 validate_point_mode(YYLTYPE *loc,
                              ^~~
glsl/ast_type.cpp:174:45: warning: unused parameter ‘state’ [-Wunused-parameter]
                     _mesa_glsl_parse_state *state,
                                             ^~~~~

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Andres Gomez <agomez@igalia.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>