[SUNRPC]: Remove SPIN_LOCK_UNLOCKED

SPIN_LOCK_UNLOCKED is deprecated, use DEFINE_SPINLOCK instead

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>