elf: Properly compute offsets of note descriptor and next note

elf: Properly compute offsets of note descriptor and next note

According to gABI, in a note entry, the note name field, not note name
size, is padded for the note descriptor.  And the note descriptor field,
not note descriptor size, is padded for the next note entry.  Also notes
are aligned to 4 bytes in 32-bit objects and 8 bytes in 64-bit objects.
Since on Linux, .note.ABI-tag and .note.gnu.build-id notes are always
aligned to 4 bytes, we need to use alignment of note section or note
segment, instead of assuming alignment based on ELF file class.

Tested on i686 and x86-64.

bfd/

	PR binutils/22444
	* elf.c (elf_read_notes): Add an argument for note aligment.
	(elf_parse_notes): Likewise.
	(_bfd_elf_make_section_from_shdr): Pass section aligment to
	elf_parse_notes.
	(bfd_section_from_phdr): Pass segment aligment to elf_read_notes.
	(elf_parse_notes): Add an argument for note aligment.  Use
	ELF_NOTE_DESC_OFFSET to get the offset of the note descriptor.
	Use ELF_NOTE_NEXT_OFFSET to get the offset of the next note
	entry.
	(elf_read_notes): Add an argument for note aligment and pass it
	to elf_parse_notes.

binutils/

	PR binutils/22444
	* readelf.c (process_notes_at): Use ELF_NOTE_DESC_OFFSET to get
	the offset of the note descriptor.  Use ELF_NOTE_NEXT_OFFSET to
	get the offset of the next note entry.

include/

	PR binutils/22444
	* elf/external.h (ELF_ALIGN_UP): New.
	(ELF_NOTE_DESC_OFFSET): Likewise.
	(ELF_NOTE_NEXT_OFFSET): Likewise.