TLV: add new "vTvLV" type for GAN

This new TLV type is specific to TS 44.318.  Contrary to the TvLV type
of TS 08.16/08.18, it has an inverted meaning of the extension (0x80)
bit:
	* if the extension bit is not set, 1-byte length
	* if the extension bit is set, 2-byte length

Futhermore, it has support for variable-length tags, where the tag part
can be optionally two bytes in length.  As this esoteric option hasn't
been seen in the wild yet, we only add encoding support but skip
decoding for now.
3 files changed