applications: serial_lte_modem: Remove modem delta FW update workaround

Working around the modem firmware bug
is now taken care of by the modem library.

Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>

applications/serial_lte_modem/src/slm_at_fota.c

@@ -376,7 +376,6 @@ void slm_fota_post_process(void)
 void slm_finish_modem_fota(int modem_lib_init_ret)
 {
  if (handle_nrf_modem_lib_init_ret(modem_lib_init_ret)) {
- char buf[40];
 
  LOG_INF("Re-initializing the modem due to"
  " ongoing modem firmware update.");
@@ -387,15 +386,5 @@ void slm_finish_modem_fota(int modem_lib_init_ret)
  */
  modem_lib_init_ret = nrf_modem_lib_init();
  handle_nrf_modem_lib_init_ret(modem_lib_init_ret);
-
- nrf_modem_at_cmd(buf, sizeof(buf), "%s", "AT%SHORTSWVER");
- if (strstr(buf, "1.3.4") || strstr(buf, "1.3.5")) {
- /* Those versions suffer from a bug that provokes UICC failure (+CEREG: 90)
- * after the update, preventing the modem from registering to the network.
- */
- LOG_INF("Applying the workaround to a modem firmware update issue...");
- nrf_modem_lib_shutdown();
- nrf_modem_lib_init();
- }
  }
 }