drivers/usb/host/ehci-platform.c: fix error return code

Convert a possibly 0 error return code to a negative one, as returned
elsewhere in the function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret;
expression e,e1,e2,e3,e4,x;
@@

(
if (\(ret != 0\|ret < 0\) || ...) { ... return ...; }
|
ret = 0
)
... when != ret = e1
*x = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\|ioremap\|ioremap_nocache\|devm_ioremap\|devm_ioremap_nocache\)(...);
... when != x = e2
    when != ret = e3
*if (x == NULL || ...)
{
  ... when != ret = e4
*  return ret;
}
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-platform.c

@@ -128,8 +128,10 @@ static int __devinit ehci_platform_probe(struct platform_device *dev)
 	}
 
 	hcd->regs = ioremap_nocache(hcd->rsrc_start, hcd->rsrc_len);
-	if (!hcd->regs)
+	if (!hcd->regs) {
+		err = -ENOMEM;
 		goto err_release_region;
+	}
 	err = usb_add_hcd(hcd, irq, IRQF_SHARED);
 	if (err)
 		goto err_iounmap;