Don't use INTDEF/INTUSE with _dl_mcount (bug 14132).

Continuing the removal of the obsolete INTDEF / INTUSE mechanism, this
patch replaces its use for _dl_mcount with use of rtld_hidden_def /
rtld_hidden_proto.

Tested for x86_64 that installed stripped shared libraries are
unchanged by the patch.

	[BZ #14132]
	* elf/dl-profile.c (_dl_mcount): Use rtld_hidden_def instead of
	INTDEF.
	* sysdeps/generic/ldsodefs.h (_dl_mcount_internal): Remove
	declaration.
	(_dl_mcount): Use rtld_hidden_proto.
	* elf/dl-runtime.c (_dl_profile_fixup): Don't use INTUSE with
	_dl_mcount.
	* elf/rtld.c (_rtld_global_ro): Likewise.