[ARM] Add armelf_linux_fdpiceabi and armelfb_linux_fdpiceabi BFD backends

[ARM] Add armelf_linux_fdpiceabi and armelfb_linux_fdpiceabi BFD backends

Initial definition of these new backends.

2018-04-25  Christophe Lyon  <christophe.lyon@st.com>
	Mickaël Guêné  <mickael.guene@st.com>

	bfd/
	* config.bfd (arm*-*-linux-*): Add arm_elf32_fdpic_be_vec and
	arm_elf32_fdpic_le_vec to targ_selvecs. Accept
	arm*-*-uclinuxfdpiceabi.
	* configure.ac: Add support for arm_elf32_fdpic_be_vec and
	arm_elf32_fdpic_le_vec.
	* configure: Regenerate.
	* elf32-arm.c (struct elf32_arm_link_hash_table): Add fdpic_p.
	(elf32_arm_link_hash_table_create): Initialize fdpic_p.
	(TARGET_LITTLE_SYM, TARGET_LITTLE_NAME, TARGET_BIG_SYM)
	(TARGET_BIG_NAME, elf_match_priority): Define for FDPIC targets.
	(elf32_arm_fdpic_link_hash_table_create): New.
	* targets.c (_bfd_target_vector): Add arm_elf32_fdpic_be_vec and
	arm_elf32_fdpic_le_vec.

	ld/
	* Makefile.am (ALL_EMULATION_SOURCES): Add
	earmelf_linux_fdpiceabi.c and earmelfb_linux_fdpiceabi.c.
	(earmelf_linux_fdpiceabi.c, earmelfb_linux_fdpiceabi.c): New rules.
	* Makefile.in: Regenerate.
	* configure.tgt (arm*-*-uclinuxfdpiceabi): Handle new target.
	* emulparams/armelf_linux_fdpiceabi.sh: New.
	* emulparams/armelfb_linux_fdpiceabi.sh: New.