Add a -w option to the linker to suppress warning and error messages.

Add a -w option to the linker to suppress warning and error messages.

	PR 29654
	* ld.h (struct ld_config_type): Add no_warnings field.
	* ldlex.h (enum option_values): Add OPTION_NO_WARNINGS.
	* lexsup.c (ld_options): Add --no-warnings.
	(parse_args): Add support for -w and --no-warnings.
	* ldmisc.c (vfinfo): Return early if the message is a warning and
	-w has been enabled.
	* ld.texi (options): Document new command line option.
	* NEWS: Mention the new feature.