Revert "ck_rwlock: Add ck_rwlock_read_latchlock operation."

This reverts commit bc7ebc62eb.

include/ck_rwlock.h

@@ -190,33 +190,6 @@ CK_ELIDE_TRYLOCK_PROTOTYPE(ck_rwlock_read, ck_rwlock_t,
 
 CK_CC_INLINE static void
 ck_rwlock_read_lock(ck_rwlock_t *rw)
-{
-
-	for (;;) {
-		while (ck_pr_load_32(&rw->writer) != 0)
-			ck_pr_stall();
-
-		ck_pr_inc_32(&rw->n_readers);
-
-		/*
-		 * Serialize with respect to concurrent write
-		 * lock operation.
-		 */
-		ck_pr_fence_atomic_load();
-
-		if (ck_pr_load_32(&rw->writer) == 0)
-			break;
-
-		ck_pr_dec_32(&rw->n_readers);
-	}
-
-	/* Acquire semantics are necessary. */
-	ck_pr_fence_load();
-	return;
-}
-
-CK_CC_INLINE static void
-ck_rwlock_read_latchlock(ck_rwlock_t *rw)
 {
 	uint32_t snapshot;