Handle TDD pattern 2 in UL TDA allocation

Add the possibility to use UL slots in TDD pattern 2. For simplicity, we
require the mixed slot to be of the same symbols in pattern 1 & 2. For
UL slots, simply use the right amount of UL TDAs, depending on which
number of UL slots among pattern 1 & 2 is bigger.

One complication is the TDA for the mixed slot. The current code assumes
that k2 has to be equal or larger than (number of DL slots +1) (because
the spec says min k2=2, but we might want to schedule DSUUU). Then,
there could be for instance the following cases:

- only pattern 1: DSUUU DSUUU ...: the mixed slot has to be reached an
  entire period in advance
- pattern 1 & 2: DSUUU DDDDD: normal mixed slot k2, e.g., like for 7DS2U
- pattern 1 & 2: DSUUU DDDSU: the mixed slot has to be reached
  N_ul2+N_dl1+1 slots in advance

I can't think of more cases right now. To avoid unscheduled slots, I put
an assertion (which could also trivially be taken out).

openair2/GNB_APP/gnb_config.c

@@ -1206,10 +1206,6 @@ static NR_ServingCellConfigCommon_t *get_scc_config(configmodule_interface_t *cf
       struct NR_TDD_UL_DL_ConfigCommon *tdd = scc->tdd_UL_DL_ConfigurationCommon;
       tdd->pattern2 = calloc_or_fail(1, sizeof(*tdd->pattern2));
       *scc->tdd_UL_DL_ConfigurationCommon->pattern2 = p2;
-      AssertFatal(p2.nrofUplinkSlots ^ scc->tdd_UL_DL_ConfigurationCommon->pattern1.nrofUplinkSlots,
-                  "UL slots in pattern1 (%ld) and pattern2 (%ld) are mutually exclusive (e.g. DDDFUU DDDD, DDDD DDDFUU)\n",
-                  scc->tdd_UL_DL_ConfigurationCommon->pattern1.nrofUplinkSlots,
-                  p2.nrofUplinkSlots);
     }
     struct NR_FrequencyInfoDL *frequencyInfoDL = scc->downlinkConfigCommon->frequencyInfoDL;
     LOG_I(RRC,