elfedit: Update help message

Update elfedit message to

$ elfedit --help
Usage: elfedit <option(s)> elffile(s)
 Update the ELF header of ELF files
 The options are:
  --input-mach [none|i386|iamcu|l1om|k1om|x86_64]
                              Set input machine type
  --output-mach [none|i386|iamcu|l1om|k1om|x86_64]
                              Set output machine type
  --input-type [none|rel|exec|dyn]
                              Set input file type
  --output-type [none|rel|exec|dyn]
                              Set output file type
  --input-osabi [none|HPUX|NetBSD|GNU|Linux|Solaris|AIX|Irix|FreeBSD|TRU64|Modesto|OpenBSD|OpenVMS|NSK|AROS|FenixOS]
                              Set input OSABI
  --output-osabi [none|HPUX|NetBSD|GNU|Linux|Solaris|AIX|Irix|FreeBSD|TRU64|Modesto|OpenBSD|OpenVMS|NSK|AROS|FenixOS]
                              Set output OSABI
  --enable-x86-feature [ibt|shstk]
                              Enable x86 feature
  --disable-x86-feature [ibt|shstk]
                              Disable x86 feature
  -h --help                   Display this information
  -v --version                Display the version number of elfedit
Report bugs to <http://www.sourceware.org/bugzilla/>

	* elfedit.c: Include "libiberty.h".
	(usage): Update help message.