Fix several mix up between octets and bytes in ELF program headers

Fix several mix up between octets and bytes in ELF program headers

When converting between addresses in ELF headers [octets] and bfd
LMA/VMA [bytes], the number of octets per byte needs to be
incorporated.

In ld, the SIZEOF_HEADERS linker script statement must be resolved to
bytes instead of octets.

include/
	* elf/internal.h (struct elf_internal_phdr): Add unit (octets)
	to several member field comments.
	(Elf_Internal_Shdr): likewise.
bfd/
	* elf.c (_bfd_elf_make_section_from_shdr): Introduce new temp
	opb.  Divide Elf_Internal_Shdr::sh_addr by opb when setting
	section LMA/VMA.
	(_bfd_elf_make_section_from_phdr): Similarly.
	(elf_fake_sections): Fix calculation of
	Elf_Internal_shdr::sh_addr from section VMA.
	(_bfd_elf_map_sections_to_segments): Fix mixup between octets
	and bytes.
	(assign_file_positions_for_load_sections): Fix calculations of
	Elf_Internal_shdr::p_vaddr and p_paddr from section LMA/VMA.  Fix
	comparison between program header address and section LMA.
	(assign_file_positions_for_non_load_sections): Likewise.
	(rewrite_elf_program_header): Likewise.  Introduce new temp opb.
	(IS_CONTAINED_BY_VMA): Add parameter opb.
	(IS_CONTAINED_BY_LMA,IS_SECTION_IN_INPUT_SEGMENT,
	INCLUDE_SECTION_IN_SEGMENT): Likewise.
	(copy_elf_program_header): Update call to ELF_SECTION_IN_SEGMENT.
	Fix calculations of p_addr_valid and p_vaddr_offset.
	* elflink.c (elf_link_add_object_symbols): Multiply section VMA
	with octets per byte when comparing against p_vaddr.
ld/
	* ldexp.c (fold_name): Return SIZEOF_HEADERS in bytes.