kvx: fix 32-bit build

bfd/
	* Makefile.am: Move elf32-kvx.lo from BFD32_BACKENDS to
	BFD64_BACKENDS.  Remove elfxx-kvx.lo from BFD32_BACKENDS.
	Remove elfxx-kvx.c from BFD32_BACKENDS_CFILES.
	* Makefile.in: Regenerate.
	* config.bfd: Adjust targ_defvec and targ_selvecs and gate them
	behind BFD64.
	* configure.ac: Add target_size=64 to kvx_elf64_*vec.
	* configure: Regenerate.
	* elfnn-kvx.c (elfNN_kvx_stub_name): Cast rel->r_addend to
	uint64_t to match format string.
	(elfNN_kvx_relocate_section): Similarly for r_offset, and
	use PRIx64 in format string.
	* targets.c (_bfd_target_vector <kvx_elf32_vec>): Move inside
	#ifdef BFD64.
ld/
	* Makefile.am: Move eelf32kvx.c from ALL_EMULATION_SOURCES to
	ALL_64_EMULATION_SOURCES.
	* Makefile.in: Regenerate.