The decoding path of TLV_TYPE_SINGLE_TV is wrong, since it is not
shifting right the tag before using it. On the other hand, the encoding
path (tlv_encode_one) is doing that, so it is clear there's a bug.
It seems that in order to workaround the bug some IEs in gsm_04_08.h (TS
24.008 and TS 44.018) were defined incorrectly (eg 0x80) while the spec
clearly assigns eg. "8" to it, and makes sure no full byte IEI collides.
Some other IEIs like GSM48_IE_GMM_CIPH_CKSN which are also of the same
type were already correctly defined as 0x08.