IB/ucm: Initialize sgid request GID attribute pointer

sgid_attr is uninitialized on the stack, initialize it to NULL.

Fixes: 3983910 ("IB/cm: Replace members of sa_path_rec with 'struct sgid_attr *'")
Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Yossi Itigin <yosefe@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/ucm.c

@@ -1000,14 +1000,11 @@ static ssize_t ib_ucm_send_sidr_req(struct ib_ucm_file *file,
 				    const char __user *inbuf,
 				    int in_len, int out_len)
 {
-	struct ib_cm_sidr_req_param param;
+	struct ib_cm_sidr_req_param param = {};
 	struct ib_ucm_context *ctx;
 	struct ib_ucm_sidr_req cmd;
 	int result;
 
-	param.private_data = NULL;
-	param.path = NULL;
-
 	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
 		return -EFAULT;