glsl: Silence unused parameter warnings

glsl: Silence unused parameter warnings

builtin_variables.cpp:1062:53: warning: unused parameter 'name_as_gs_input' [-Wunused-parameter]
                                         const char *name_as_gs_input)
                                                     ^
builtin_functions.cpp:4774:47: warning: unused parameter 'intrinsic_name' [-Wunused-parameter]
                                   const char *intrinsic_name,
                                               ^
builtin_functions.cpp:4907:66: warning: unused parameter 'state' [-Wunused-parameter]
 _mesa_glsl_find_builtin_function_by_name(_mesa_glsl_parse_state *state,
                                                                  ^
builtin_functions.cpp:4915:49: warning: unused parameter 'num_arguments' [-Wunused-parameter]
                                        unsigned num_arguments,
                                                 ^
builtin_functions.cpp:4916:49: warning: unused parameter 'flags' [-Wunused-parameter]
                                        unsigned flags)
                                                 ^
ir_print_visitor.cpp:589:37: warning: unused parameter 'ir' [-Wunused-parameter]
 ir_print_visitor::visit(ir_barrier *ir)
                                     ^
linker.cpp:3212:48: warning: unused parameter 'ctx' [-Wunused-parameter]
 build_program_resource_list(struct gl_context *ctx,
                                                ^
standalone_scaffolding.cpp:65:57: warning: unused parameter ‘id’ [-Wunused-parameter]
 _mesa_shader_debug(struct gl_context *, GLenum, GLuint *id,
                                                         ^

v2: Rebase on top of GL_ARB_shader_image_size work (especially
58a86897).  Silence more warnings added by that work.

v3: Remove mention of the removed parameter from comments.  Suggested by
Iago.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu> [v1]
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Cc: "Martin Peres <martin.peres@linux.intel.com>"