crypto: caam - Fix null dereference at error path

caam_remove already removes the debugfs entry, so we need to remove the one
immediately before calling caam_remove.

This fix a NULL dereference at error paths is caam_probe fail.

Fixes: 67c2315def06 ("crypto: caam - add Queue Interface (QI) backend support")

Tested-by: Ryan Harkin <ryan.harkin@linaro.org>
Cc: "Horia Geantă" <horia.geanta@nxp.com>
Cc: Aymen Sghaier <aymen.sghaier@nxp.com>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Cc: <stable@vger.kernel.org> # 4.12+
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/ctrl.c

@@ -815,9 +815,6 @@ static int caam_probe(struct platform_device *pdev)
 	return 0;
 
 caam_remove:
-#ifdef CONFIG_DEBUG_FS
-	debugfs_remove_recursive(ctrlpriv->dfs_root);
-#endif
 	caam_remove(pdev);
 	return ret;