opcodes: Use autoconf to check for `bfd_mips_elf_get_abiflags' in BFD

opcodes: Use autoconf to check for `bfd_mips_elf_get_abiflags' in BFD

Fix a regression introduced with commit 5e7fc731f80e ("MIPS/opcodes:
Also set disassembler's ASE flags from ELF structures"), further updated
with commit 4df995c77118 ("MIPS/opcodes: Also set disassembler's ASE
flags from ELF structures"), and use autoconf to check for the presence
of `bfd_mips_elf_get_abiflags' in BFD.

	opcodes/
	* mips-dis.c (set_default_mips_dis_options): Use
	HAVE_BFD_MIPS_ELF_GET_ABIFLAGS rather than BFD64 to guard the
	call to `bfd_mips_elf_get_abiflags'.
	* configure.ac: Check for `bfd_mips_elf_get_abiflags' in BFD.
	* Makefile.am (CONFIG_STATUS_DEPENDENCIES): Add `libbfd.la'.
	* aclocal.m4: Regenerate.
	* configure: Regenerate.
	* config.in: Regenerate.
	* Makefile.in: Regenerate.