misc: xilinx_sdfec: Use memdup_user() as a cleanup

Fix coccicheck warning which recommends to use memdup_user().

This patch fixes the following coccicheck warnings:

drivers/misc/xilinx_sdfec.c:652:8-15: WARNING opportunity for memdup_user
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Link: https://lore.kernel.org/r/1587524330-119776-1-git-send-email-zou_wei@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/xilinx_sdfec.c

@@ -649,14 +649,9 @@ static int xsdfec_add_ldpc(struct xsdfec_dev *xsdfec, void __user *arg)
 	struct xsdfec_ldpc_params *ldpc;
 	int ret, n;
 
-	ldpc = kzalloc(sizeof(*ldpc), GFP_KERNEL);
-	if (!ldpc)
-		return -ENOMEM;
-
-	if (copy_from_user(ldpc, arg, sizeof(*ldpc))) {
-		ret = -EFAULT;
-		goto err_out;
-	}
+	ldpc = memdup_user(arg, sizeof(*ldpc));
+	if (IS_ERR(ldpc))
+		return PTR_ERR(ldpc);
 
 	if (xsdfec->config.code == XSDFEC_TURBO_CODE) {
 		ret = -EIO;