Remove Mutexes in phy_stub_UE.c

Various mutexes are present in the phy_stub_UE.c file. However, it will
only be run in a single thread; the multiple-thread implementation also
runs the higher layers concurrently, which leads to races and segfaults.
Therefore, remove these mutexes, as we don't need them.

openair2/PHY_INTERFACE/IF_Module.h

@@ -203,17 +203,6 @@ typedef struct IF_Module_s{
   pthread_mutex_t if_mutex;
 } IF_Module_t;
 
-// These mutex is used for multiple UEs L2 FAPI simulator.
-// Each UEs set these value in UL and UL_INFO is shared in all UE's thread.
-typedef struct {
-  pthread_mutex_t rx_mutex;
-  pthread_mutex_t crc_mutex;
-  pthread_mutex_t sr_mutex;
-  pthread_mutex_t harq_mutex;
-  pthread_mutex_t cqi_mutex;
-  pthread_mutex_t rach_mutex;
-} FILL_UL_INFO_MUTEX_t;
-
 /*Initial */
 IF_Module_t *IF_Module_init(int Mod_id);
 void IF_Module_kill(int Mod_id);