opcodes: add support for eBPF

opcodes: add support for eBPF

This patch adds support for the Linux kernel eBPF architecture to the
opcodes.  The port is based on CGEN.

opcodes/ChangeLog:

2019-05-23  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* configure.ac (SHARED_DEPENDENCIES): Add case for bfd_bpf_arch.
	* configure: Regenerated.
	* Makefile.am: Add rules for the files generated from cpu/bpf.cpu
	and cpu/bpf.opc.
	(HFILES): Add bpf-desc.h and bpf-opc.h.
	(TARGET_LIBOPCODES_CFILES): Add bpf-asm.c, bpf-desc.c, bpf-dis.c,
	bpf-ibld.c and bpf-opc.c.
	(BPF_DEPS): Define.
	* Makefile.in: Regenerated.
	* disassemble.c (ARCH_bpf): Define.
	(disassembler): Add case for bfd_arch_bpf.
	(disassemble_init_for_target): Likewise.
	(enum epbf_isa_attr): Define.
	* disassemble.h: extern print_insn_bpf.
	* bpf-asm.c: Generated.
	* bpf-opc.h: Likewise.
	* bpf-opc.c: Likewise.
	* bpf-ibld.c: Likewise.
	* bpf-dis.c: Likewise.
	* bpf-desc.h: Likewise.
	* bpf-desc.c: Likewise.