osmo-pcu[master]: add KPI counter to count bytes for RLC and LLC frames

Patch Set 2:

(1 comment)

https://gerrit.osmocom.org/#/c/145/2/src/bts.cpp File src/bts.cpp:

Line 79: { "rlc.ul_payload_bytes", "RLC UL Payload Bytes "},

I'd prefer if DL and UL were spelled out,

As indicated, UL and DL have quite fixed meaning inside the cellular world, and we use them in various places. Unlike Rx and Tx, UL and DL are well-defined and don't depend on the point-of-view of the observer. Rx of the MS is different than Rx of the PCU. PCU Rx from Um interface is different direction than Rx frm SGSN on Gb interface, so that's very confusing. UL and DL leave no room for (mis)interpretation.