fscrypt: remove reachable WARN in fscrypt_setup_iv_ino_lblk_32_key()

I_CREATING isn't actually set until the inode has been assigned an inode
number and inserted into the inode hash table.  So the WARN_ON() in
fscrypt_setup_iv_ino_lblk_32_key() is wrong, and it can trigger when
creating an encrypted file on ext4.  Remove it.

This was sometimes causing xfstest generic/602 to fail on ext4.  I
didn't notice it before because due to a separate oversight, new inodes
that haven't been assigned an inode number yet don't necessarily have
i_ino == 0 as I had thought, so by chance I never saw the test fail.

Fixes: a992b20c ("fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()")
Reported-by: Theodore Y. Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20201031004556.87862-1-ebiggers@kernel.orgSigned-off-by: Eric Biggers <ebiggers@google.com>

fs/crypto/keysetup.c

@@ -269,9 +269,7 @@ static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci,
 	 * New inodes may not have an inode number assigned yet.
 	 * Hashing their inode number is delayed until later.
 	 */
-	if (ci->ci_inode->i_ino == 0)
-		WARN_ON(!(ci->ci_inode->i_state & I_CREATING));
-	else
+	if (ci->ci_inode->i_ino)
 		fscrypt_hash_inode_number(ci, mk);
 	return 0;
 }