net: wrong test in inet_ehash_locks_alloc()

In commit 9db66bdc (net: convert
TCP/DCCP ehash rwlocks to spinlocks), I forgot to change one
occurrence of rwlock_t to spinlock_t

I believe sizeof(raw_spinlock_t) might be > 0 on !CONFIG_SMP if
CONFIG_DEBUG_SPINLOCK while sizeof(raw_rwlock_t) should be 0 in this
case.

Fortunatly, CONFIG_DEBUG_SPINLOCK adds fields to both spinlock_t and
rwlock_t, but at this might change in the future (being able to debug
spinlocks but not rwlocks for example), better to be safe.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/inet_hashtables.h

@@ -182,7 +182,7 @@ static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
 		size = 2048;
 	if (nr_pcpus >= 32)
 		size = 4096;
-	if (sizeof(rwlock_t) != 0) {
+	if (sizeof(spinlock_t) != 0) {
 #ifdef CONFIG_NUMA
 		if (size * sizeof(spinlock_t) > PAGE_SIZE)
 			hashinfo->ehash_locks = vmalloc(size * sizeof(spinlock_t));