mtd: spear_smi: add NULL check on devm_kzalloc() return value

Check return value from call to devm_kzalloc()
in order to prevent a NULL pointer dereference.

This issue was detected using Coccinelle and the following semantic patch:

@@
expression x;
identifier fld;
@@

* x = devm_kzalloc(...);
  ... when != x == NULL
  x->fld
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/devices/spear_smi.c

@@ -775,6 +775,8 @@ static int spear_smi_probe_config_dt(struct platform_device *pdev,
 	pdata->board_flash_info = devm_kzalloc(&pdev->dev,
 					       sizeof(*pdata->board_flash_info),
 					       GFP_KERNEL);
+	if (!pdata->board_flash_info)
+		return -ENOMEM;
 
 	/* Fill structs for each subnode (flash device) */
 	while ((pp = of_get_next_child(np, pp))) {