Add support to readelf for reading FreeBSD ELF core notes.

Add support to readelf for reading FreeBSD ELF core notes.

binutils/ChangeLog:

	* readelf.c (get_freebsd_elfcore_note_type): New
	(process_note): Add support for FreeBSD core notes.

include/ChangeLog:

	* elf/common.h (NT_FREEBSD_THRMISC): Define.
	(NT_FREEBSD_PROCSTAT_PROC): Define.
	(NT_FREEBSD_PROCSTAT_FILES): Define.
	(NT_FREEBSD_PROCSTAT_VMMAP): Define.
	(NT_FREEBSD_PROCSTAT_GROUPS): Define.
	(NT_FREEBSD_PROCSTAT_UMASK): Define.
	(NT_FREEBSD_PROCSTAT_RLIMIT): Define.
	(NT_FREEBSD_PROCSTAT_OSREL): Define.
	(NT_FREEBSD_PROCSTAT_PSSTRINGS): Define.
	(NT_FREEBSD_PROCSTAT_AUXV): Define.