lockd: Rename struct nlm_share to lockd_share

lockd: Rename struct nlm_share to lockd_share

As part of the effort to enable lockd's server-side XDR functions to
be generated from the NLM protocol specification (using xdrgen), the
internal type names must be changed to avoid conflicts with the
machine-generated type names.

Rename struct nlm_share to struct lockd_share to avoid conflicts with
the NLMv3 XDR type definitions that will be introduced when svcproc.c
is converted to use xdrgen.

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