aix: implement R_TOCU and R_TOCL relocations

aix: implement R_TOCU and R_TOCL relocations

Implement support for largetoc on XCOFF.
R_TOCU and R_TOCL are referenced by the new BFD defines:
BFD_RELOC_PPC_TOC16_HI and BFD_RELOC_PPC_TOC16_LO.
A new toc storage class is added XMC_TE.

In order to correctly handle R_TOCU, the logic behind
xcoff_reloc_type_toc is changed to compute the whole TOC offset
instead of just the difference between the "link" offset and the
"assembly" offset.

In gas, add a function to transform addis format used by AIX
"addis RT, D(RA)" into the ELF format "addis RT, RA, SI".

bfd/
	* reloc.c (BFD_RELOC_PPC_TOC16_HI, BFD_RELOC_PPC_TOC16_LO):
	New relocations.
	* bfd-in2.h: Regenerate.
	* libbfd.h: Regenerate.
	* coff-rs6000.c (xcoff_calculate_relocation): Call
	xcoff_reloc_type_toc for R_TOCU and R_TOCL.
	(xcoff_howto_table): Remove src_mask for TOC relocations.
	Add R_TOCU and R_TOCL howtos.
	(_bfd_xcoff_reloc_type_lookup): Add cases for
	BFD_RELOC_PPC_TOC16_HI and BFD_RELOC_PPC_TOC16_LO.
	(xcoff_reloc_type_toc): Compute the whole offset.
	Implement R_TOCU and R_TOCL.
	* coff64-rs6000.c (xcoff64_calculate_relocation):
	Likewise.
	(xcoff64_howto_table): Likewise.
	(xcoff64_reloc_type_lookup): Likewise.
gas/
	* config/tc-ppc.c (ppc_xcoff_suffix): New function.
	(MAP, MAP32, MAP64): New macros for XCOFF.
	(ppc_xcoff_fixup_addis): New function.
	(ppc_is_toc_sym): Handle XMC_TE.
	(fixup_size): Add cases for BFD_RELOC_PPC_TOC16_HI and
	BFD_RELOC_PPC_TOC16_LO.
	(md_assemble): Call ppc_xcoff_fixup_addis for XCOFF.
	(ppc_change_csect): Handle XMC_TE.
	(ppc_tc): Enable .tc symbols to have only a XMC_TC or XMC_TE
	storage class.
	(ppc_symbol_new_hook): Handle XMC_TE.
	(ppc_frob_symbol): Likewise.
	(ppc_fix_adjustable): Likewise.
	(md_apply_fix): Handle BFD_RELOC_PPC_TOC16_HI and
	BFD_RELOC_PPC_TOC16_LO.
ld/
	* scripttempl/aix.sc: Add .te to .data section.
	* testsuite/ld-powerpc/aix52.exp: Add test structure for AIX7+.
	Add aix-largetoc-1 test.
	* testsuite/ld-powerpc/aix-largetoc-1-32.d: New test.
	* testsuite/ld-powerpc/aix-largetoc-1-64.d: New test.
	* testsuite/ld-powerpc/aix-largetoc-1.ex: New test.
	* testsuite/ld-powerpc/aix-largetoc-1.s: New test.