ipaccess: fix buffer overread in ipacc_parse_supp_flags()
The loop used OSMO_MAX(e->len, 4), which iterates at least 4 times even when the IE is shorter than 4 bytes, causing a buffer overread. Replace with OSMO_MIN(e->len, sizeof(u32)) to cap the iteration both at the actual IE length and at the uint32_t accumulator size.
This commit raises the LAPD RSL N200 (retransmission) counter for Nokia RSL links. The reason is that the readiness of the TRX is not signalled (OML) nor can be queried from the BTS in any way, and on larger macro setups the TRX reset takes ~15 seconds, thus the RSL bootstrap times out before the TRX becomes ready.
This issue presents itself with UltraSite types, does not affect InSite or MetroSite (the later two are "integrated TRX" units). More modern macro setups like the Flexi or Multiradio are likely affected.
Runtime tested with InSite and UltraSite (multi-TRX).
