SUNRPC: move the pool_map definitions (back) into svc.c

[ Upstream commit cf0e124e ]

These definitions are not used outside of svc.c, and there is no
evidence that they ever have been.  So move them into svc.c
and make the declarations 'static'.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>