usb: misc: brcmstb-usb-pinmap: check return value after calling platform_get_resource()

It will cause null-ptr-deref if platform_get_resource() returns NULL,
we need check the return value.

Fixes: 517c4c44b323 ("usb: Add driver to allow any GPIO to be used for 7211 USB signals")
Cc: stable <[e-mail]>
Signed-off-by: Yang Yingliang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/misc/brcmstb-usb-pinmap.c

···
 		return -EINVAL;
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r)
+		return -EINVAL;
 
 	pdata = devm_kzalloc(&pdev->dev,
 			     sizeof(*pdata) +