Add support for DT_MIPS_RLD_MAP_REL.

Add support for DT_MIPS_RLD_MAP_REL.

This tag makes it possible to access the debug map when debugging position
independent executables.

bfd/

	* elfxx-mips.c (_bfd_mips_elf_create_dynamic_sections): Use executable
	instead of !shared to indicate an application vs shared library.
	(_bfd_mips_elf_size_dynamic_sections): Likewise.
	(_bfd_mips_elf_finish_dynamic_sections): Handle DT_MIPS_RLD_MAP_REL.
	(_bfd_mips_elf_get_target_dtag): Likewise.

binutils/

	* readelf.c (get_mips_dynamic_type): Handle DT_MIPS_RLD_MAP_REL.

include/

	* elf/mips.h (DT_MIPS_RLD_MAP_REL): New macro.

ld/testsuite/

	* ld-mips-elf/pic-and-nonpic-3b.ad: Adjust for extra dynamic tag.
	* ld-mips-elf/pic-and-nonpic-4b.ad: Likewise.
	* ld-mips-elf/pic-and-nonpic-5b.ad: Likewise.
	* ld-mips-elf/pic-and-nonpic-6-n32.ad: Likewise.
	* ld-mips-elf/pic-and-nonpic-6-n64.ad: Likewise.
	* ld-mips-elf/pic-and-nonpic-6-o32.ad: Likewise.
	* ld-mips-elf/tlsdyn-o32-1.d: Likewise.
	* ld-mips-elf/tlsdyn-o32-1.got: Likewise.
	* ld-mips-elf/tlsdyn-o32-2.d: Likewise.
	* ld-mips-elf/tlsdyn-o32-2.got: Likewise.
	* ld-mips-elf/tlsdyn-o32-3.d: Likewise.
	* ld-mips-elf/tlsdyn-o32-3.got: Likewise.
	* ld-mips-elf/tlsdyn-o32.d: Likewise.
	* ld-mips-elf/tlsdyn-o32.got: Likewise.
	* ld-mips-elf/pie-n32.d: New file.
	* ld-mips-elf/pie-n64.d: Likewise.
	* ld-mips-elf/pie-o32.d: Likewise.
	* ld-mips-elf/pie.s: Likewise.
	* ld-mips-elf/mips-elf.exp: Add new tests.