fscrypt: remove WARN_ON_ONCE() when decryption fails

If decrypting a block fails, fscrypt did a WARN_ON_ONCE().  But WARN is
meant for kernel bugs, which this isn't; this could be hit by fuzzers
using fault injection, for example.  Also, there is already a proper
warning message logged in fscrypt_do_page_crypto(), so the WARN doesn't
add much.

Just remove the unnessary WARN.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/crypto/bio.c

@@ -37,12 +37,10 @@ static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
 		int ret = fscrypt_decrypt_page(page->mapping->host, page,
 				PAGE_SIZE, 0, page->index);
 
-		if (ret) {
-			WARN_ON_ONCE(1);
+		if (ret)
 			SetPageError(page);
-		} else if (done) {
+		else if (done)
 			SetPageUptodate(page);
-		}
 		if (done)
 			unlock_page(page);
 	}