staging: r8188eu: fix memleak in rtw_wx_set_enc_ext

Free the param struct if the caller sets an unsupported algorithm
and we return an error.

Fixes: 2b42bd58b321 ("staging: r8188eu: introduce new os_dep dir for RTL8188eu driver")
Cc: stable <[e-mail]>
Signed-off-by: Martin Kaiser <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/r8188eu/os_dep/ioctl_linux.c

···
 	struct ieee_param *param = NULL;
 	struct iw_point *pencoding = &wrqu->encoding;
 	struct iw_encode_ext *pext = (struct iw_encode_ext *)extra;
-	int ret = 0;
+	int ret = -1;
 
 	param_len = sizeof(struct ieee_param) + pext->key_len;
 	param = kzalloc(param_len, GFP_KERNEL);
···
 		alg_name = "CCMP";
 		break;
 	default:
-		return -1;
+		goto out;
 	}
 
 	strlcpy((char *)param->u.crypt.alg, alg_name, IEEE_CRYPT_ALG_NAME_LEN);
···
 
 	ret =  wpa_set_encryption(dev, param, param_len);
 
+out:
 	kfree(param);
 	return ret;
 }