Lock HAL's shmem on write to let a reader know about potential inconsistent
data

List below indicates which functions requires a lock (marked as "UPDATE").
minipc:
--halexp_lock_cmd:
  --hal_port_enable_tracking - not
  --hal_port_start_lock - UPDATE
  --hal_port_check_lock - not
--halexp_pps_cmd
  --rts_adjust_phase - not
  --shw_pps_gen_adjust - not
  --shw_pps_gen_busy - not
  --hal_port_pshifter_busy - not
  --shw_pps_gen_enable_output - not

hal_port_update_all:
--poll_rts_state - not
--hal_port_poll_sfp:
  --shw_sfp_module_scan - not
  --hal_port_insert_sfp - UPDATE
  --hal_port_remove_sfp - UPDATE
--hal_port_fsm - UPDATE
Signed-off-by: Adam Wujek <adam.wujek@cern.ch>