ssb: add extra checks when configuring SSB

this is to avoid invalid configs that later on cause segfaults, etc.

e.g.:

    0 0x7f397adf64a3  (/lib/x86_64-linux-gnu/libc.so.6+0xbb4a3)
    1 0x7f397cc8c6ce  (/usr/lib/x86_64-linux-gnu/libasan.so.4+0x796ce)
    2 0x55b921d61707 in srsran_vec_cf_copy /mnt/data/jenkins/workspace/srslte_ogt_trial_builder_x86-ubuntu1804-asan/srsLTE/lib/src/phy/utils/vector.c:226
    3 0x55b921d3b1d4 in ssb_demodulate /mnt/data/jenkins/workspace/srslte_ogt_trial_builder_x86-ubuntu1804-asan/srsLTE/lib/src/phy/sync/ssb.c:632
    4 0x55b921d3d8ce in srsran_ssb_csi_measure /mnt/data/jenkins/workspace/srslte_ogt_trial_builder_x86-ubuntu1804-asan/srsLTE/lib/src/phy/sync/ssb.c:905
    5 0x55b9215dc20f in srsue::nr::cc_worker::measure_csi() /mnt/data/jenkins/workspace/srslte_ogt_trial_builder_x86-ubuntu1804-asan/srsLTE/srsue/src/phy/nr/cc_worker.cc:373
    6 0x55b9215dd216 in srsue::nr::cc_worker::work_dl() /mnt/data/jenkins/workspace/srslte_ogt_trial_builder_x86-ubuntu1804-asan/srsLTE/srsue/src/phy/nr/cc_worker.cc:483
    7 0x55b9215f9c69 in srsue::nr::sf_worker::work_imp() /mnt/data/jenkins/workspace/srslte_ogt_trial_builder_x86-ubuntu1804-asan/srsLTE/srsue/src/phy/nr/sf_worker.cc:78
    8 0x55b921c47cc6 in srsran::thread_pool::worker::run_thread() /mnt/data/jenkins/workspace/srslte_ogt_trial_builder_x86-ubuntu1804-asan/srsLTE/lib/src/common/thread_pool.cc:48
    9 0x55b92152ea0b in srsran:🧵:thread_function_entry(void*) /mnt/data/jenkins/workspace/srslte_ogt_trial_builder_x86-ubuntu1804-asan/srsLTE/lib/include/srsran/common/threads.h:103
    10 0x7f397c9fb6da in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x76da)
    11 0x7f397ae5c71e in __clone (/lib/x86_64-linux-gnu/libc.so.6+0x12171e)

lib/src/phy/sync/ssb.c

@@ -415,7 +415,8 @@ static inline int ssb_get_t_offset(srsran_ssb_t* q, uint32_t ssb_idx)
 int srsran_ssb_set_cfg(srsran_ssb_t* q, const srsran_ssb_cfg_t* cfg)
 {
   // Verify input parameters
-  if (q == NULL || cfg == NULL) {
+  if (q == NULL || cfg == NULL || cfg->pattern == SRSRAN_SSB_PATTERN_INVALID ||
+      cfg->duplex_mode == SRSRAN_DUPLEX_MODE_INVALID) {
     return SRSRAN_ERROR_INVALID_INPUTS;
   }