Remove locking infrastructure from activation paths

Remove locking infrastructure from activation paths

Basic LV functions:

  activate_lv(), deactivate_lv(),
  suspend_lv(), resume_lv()

were routed through the locking infrastruture on the way to:

  lv_activate_with_filter(), lv_deactivate(),
  lv_suspend_if_active(), lv_resume_if_active()

This commit removes the locking infrastructure from the
middle and calls the later functions directly from the former.

There were a couple of ancillary steps that the locking
infrastructure added along the way which are still included:

  - critical section inc/dec during suspend/resume
  - checking for active component LVs during activate

The "activation" file lock (serializing activation) has not
been kept because activation commands have been changed to
take the VG file lock exclusively which makes the activation
lock unused and unnecessary.