ONIE system information command

Add a new command, onie-sys-info, that dispalys information in a
manner similar to the uname command.

Most of the information comes from the /etc/machine.conf file.

The board serial number comes from architecture specific or platform
specific code loaded from /bin/onie-sys-info-arch or
/bin/onie-sys-info-platform respectively.

COMMAND LINE OPTIONS

	The default is to dump the ONIE platform (-p).

	-h
		Help.  Print this message.

	-s
		Serial Number

	-v
		ONIE version string

	-i
		ONIE vendor ID.  Print the ONIE vendor's IANA enterprise number.

	-m
		ONIE machine string

	-r
		ONIE machine revision string

	-p
		ONIE platform string.  This is the default.

	-c
		ONIE CPU architecture

	-a
		Dump all information.