lockd: Remove unneeded initialization of file_lock::c.flc_flags

lockd: Remove unneeded initialization of file_lock::c.flc_flags

Since commit 75c7940d2a86 ("lockd: set missing fl_flags field when
retrieving args"), nlmsvc_retrieve_args() initializes the flc_flags
field. svcxdr_decode_lock() no longer needs to do this.

This clean up removes one dependency on the nlm_lock:fl field. No
behavior change is expected.

Analysis:

svcxdr_decode_lock() is called by:

nlm4svc_decode_testargs()
nlm4svc_decode_lockargs()
nlm4svc_decode_cancargs()
nlm4svc_decode_unlockargs()

nlm4svc_decode_testargs() is used by:
- NLMPROC4_TEST and NLMPROC4_TEST_MSG, which call nlmsvc_retrieve_args()
- NLMPROC4_GRANTED and NLMPROC4_GRANTED_MSG, which don't pass the
  lock's file_lock to the generic lock API

nlm4svc_decode_lockargs() is used by:
- NLMPROC4_LOCK and NLM4PROC4_LOCK_MSG, which call nlmsvc_retrieve_args()
- NLMPROC4_UNLOCK and NLM4PROC4_UNLOCK_MSG, which call nlmsvc_retrieve_args()
- NLMPROC4_NM_LOCK, which calls nlmsvc_retrieve_args()

nlm4svc_decode_cancargs() is used by:
- NLMPROC4_CANCEL and NLMPROC4_CANCEL_MSG, which call nlmsvc_retrieve_args()

nlm4svc_decode_unlockargs() is used by:
- NLMPROC4_UNLOCK and NLMPROC4_UNLOCK_MSG, which call nlmsvc_retrieve_args()

All callers except GRANTED/GRANTED_MSG eventually call
nlmsvc_retrieve_args() before using nlm_lock::fl.c.flc_flags. Thus
this change is safe.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>