Missing relocation R_PPC_VLE_ADDR20 and add VLE flag to details in readelf

Missing relocation R_PPC_VLE_ADDR20 and add VLE flag to details in readelf

include/
	* elf/ppc.h (R_PPC_VLE_ADDR20): New relocation.
bfd/
	* elf32-ppc.c (ppc_elf_howto_raw): Add R_PPC_VLE_ADDR20.
	(ppc_elf_check_relocs): Handle it.
	(ppc_elf_vle_split20): New function.
	(ppc_elf_relocate_section): Handle R_PPC_VLE_ADDR20.
binutils/
	* readelf.c (get_elf_section_flags): Add VLE.
	(process_section_headers): Add VLE key to details.
gas/
	* config/tc-ppc.c (md_parse_option): Handle "mno-vle" flag.
	(ppc_elf_section_letter): New function.
	* config/tc-ppc.h (md_elf_section_letter): New.
	* testsuite/gas/elf/section10.d: Adjust for VLE.