KEYS: trusted: Fix memory leak on object td

Two error return paths are neglecting to free allocated object td,
causing a memory leak. Fix this by returning via the error return
path that securely kfree's td.

Fixes clang scan-build warning:
security/keys/trusted-keys/trusted_tpm1.c:496:10: warning: Potential
memory leak [unix.Malloc]

Cc: stable@vger.kernel.org
Fixes: 5df16caada ("KEYS: trusted: Fix incorrect handling of tpm_get_random()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

security/keys/trusted-keys/trusted_tpm1.c

@@ -493,10 +493,12 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
 
 	ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE);
 	if (ret < 0)
-		return ret;
+		goto out;
 
-	if (ret != TPM_NONCE_SIZE)
-		return -EIO;
+	if (ret != TPM_NONCE_SIZE) {
+		ret = -EIO;
+		goto out;
+	}
 
 	ordinal = htonl(TPM_ORD_SEAL);
 	datsize = htonl(datalen);