x86: Add DT_PLTRELSZ/DT_PLTREL/DT_JMPREL for PLT relocation

x86: Add DT_PLTRELSZ/DT_PLTREL/DT_JMPREL for PLT relocation

x86, PLT relocation may contain R_386_TLS_DESC or R_X86_64_TLSDESC
even though there is no real PLT.  We need to add DT_PLTRELSZ, DT_PLTREL
and DT_JMPREL if there is a .rel.plt/.rela.plt section.

bfd/

	* elf32-i386.c (elf_i386_size_dynamic_sections): Alwasys add
	DT_PLTRELSZ, DT_PLTREL and DT_JMPREL for .rel.plt section.
	* elf64-x86-64.c (elf_x86_64_size_dynamic_sections): Alwasys
	add DT_PLTRELSZ, DT_PLTREL and DT_JMPREL for .rela.plt section.

ld/

	* testsuite/ld-i386/tlsdesc2.d: New test.
	* testsuite/ld-x86-64/tlsdesc2.d: Likewise.