Remove SH-5 remnants

git commit 211dc24b removed most sh5 and sh64 SuperH support, after
they were obsoleted by git commit 2b213129.  This patch removes a
few remaining pieces that should have gone with 211dc24b.

include/
	* elf/sh.h (STO_SH5_ISA32, SHF_SH5_ISA32, SHF_SH5_ISA32_MIXED),
	(SHT_SH5_CR_SORTED, STT_DATALABEL): Delete.
bfd/
	* elf32-sh.c (sh_elf_relocate_section): Remove STO_SH5_ISA32
	processing.