om2k: Add option to limit OML version during negotiation

Starting from G12R13 the MCTR swiches to BSC controlled mode. And
although we think we know how to configure it (via MCTR Conf Req),
something doesn't work right and the timeslot configuration is not
accepted. (TS Conf Result shows "Data not according to request").

So as a workaround for now, we use this version of the protocol where
we don't configure the MCTR (it's in "BTS controlled mode") and with
this protocol, the BTS accepts our timeslot config and we can bring
the system up.

This commit add a generic option to limit either OML or RSL IWD
version to any value. It also keeps track of the actual negotation
version so we can react to it in other places of the code.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Change-Id: I8f0b0ba72056ea4250fe490e7a38630c77c04f65

better version limit

Change-Id: Ia789f8ede3eab7eeca6c759da0109e0b53398f60
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index 1d02e39..c2115a6 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -1135,6 +1135,10 @@
 				struct gsm_abis_mo mo;
 			} tf;
 			uint32_t use_superchannel:1;
+			struct {
+				uint16_t limit;
+				uint16_t active;
+			} om2k_version[16];
 		} rbs2000;
 		struct {
 			uint8_t bts_type;