i386: Don't use ix86_tune_ctrl_string in parse_mtune_ctrl_str

i386: Don't use ix86_tune_ctrl_string in parse_mtune_ctrl_str

There are

static void
parse_mtune_ctrl_str (bool dump)
{
  if (!ix86_tune_ctrl_string)
    return;

parse_mtune_ctrl_str is only called from set_ix86_tune_features, which
is only called from ix86_function_specific_restore and
ix86_option_override_internal.  parse_mtune_ctrl_str shouldn't use
ix86_tune_ctrl_string which is defined with global_options.  Instead,
opts should be passed to parse_mtune_ctrl_str.

	PR target/91399
	* config/i386/i386-options.c (set_ix86_tune_features): Add an
	argument of a pointer to struct gcc_options and pass it to
	parse_mtune_ctrl_str.
	(ix86_function_specific_restore): Pass opts to
	set_ix86_tune_features.
	(ix86_option_override_internal): Likewise.
	(parse_mtune_ctrl_str): Add an argument of a pointer to struct
	gcc_options and use it for x_ix86_tune_ctrl_string.