net/sunrpc/svc.c: suppress unintialized var warning

net/sunrpc/svc.c: In function '__svc_create_thread':
net/sunrpc/svc.c:587: warning: 'oldmask.bits[0u]' may be used uninitialized in this function

Cc: Neil Brown <neilb@suse.de>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Tom Tucker <tom@opengridcomputing.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>