cleanup means:
- typo: susbend -> suspend
- call nr_pdcp_manager_unlock() where needed
- simplify LOG_XX (remove __FILE__, __LINE__, __FUNCTION__)

note:
nr_pdcp_release_srb() and nr_pdcp_release_drb() don't use
nr_pdcp_release_drb() because they modify the arrays, so
it does not make sense to "abstract" the accesses to
->srb and ->drb.