gss_krb5: Fix the error handling path for crypto_sync_skcipher_setkey

If we fail to call crypto_sync_skcipher_setkey, we should free the
memory allocation for cipher, replace err_return with err_free_cipher
to free the memory of cipher.

Fixes: 4891f2d008e4 ("gss_krb5: import functionality to derive keys into the kernel")
Signed-off-by: Gaosheng Cui <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Signed-off-by: Chuck Lever <[e-mail]>

net/sunrpc/auth_gss/gss_krb5_keys.c

···
 		goto err_return;
 	blocksize = crypto_sync_skcipher_blocksize(cipher);
 	if (crypto_sync_skcipher_setkey(cipher, inkey->data, inkey->len))
-		goto err_return;
+		goto err_free_cipher;
 
 	ret = -ENOMEM;
 	inblockdata = kmalloc(blocksize, gfp_mask);