cleanup - remove unnecessary calls to get_cpu_freq_GHz

The one in lte-enb.c disrupts the realtime. Using a B200mini with
20MHz bandwidth leads to the UE unable to connect for it seesms like
the UL and DL are not properly time synched because of this sleep
of one second that happens after the USRP streaming has started.
We see some random access attempts but the decoded preamble is
wrong.

This may be dependant on the setup. I had sporadic errors with
a B210, where sometimes the UE could connect and sometimes not.

(cherry picked from commit 5a61f994)

targets/RT/USER/lte-enb.c

@@ -164,13 +164,6 @@ extern void add_subframe(uint16_t *frameP, uint16_t *subframeP, int offset);
 
 
 static inline int rxtx(PHY_VARS_eNB *eNB,eNB_rxtx_proc_t *proc, char *thread_name) {
-
-  static double cpu_freq_GHz = 0.0;
-
-  if (cpu_freq_GHz == 0.0)
-    cpu_freq_GHz = get_cpu_freq_GHz();
-
-
   start_meas(&softmodem_stats_rxtx_sf);
 
   // *******************************************************************

targets/RT/USER/lte-softmodem.c

@@ -1131,8 +1131,6 @@ int main( int argc, char **argv )
 
   printf("Runtime table\n");
   fill_modeled_runtime_table(runtime_phy_rx,runtime_phy_tx);
-  cpuf=get_cpu_freq_GHz();
-  
 
 
 #ifndef DEADLINE_SCHEDULER