mfd: omap-usb-host: get rid of build warning

Fixes the below build warning when driver is built-in.

drivers/mfd/omap-usb-host.c:750:12: warning:
‘usbhs_omap_remove’ defined but not used [-Wunused-function]
Signed-off-by: Roger Quadros <rogerq@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>

drivers/mfd/omap-usb-host.c

@@ -791,7 +791,7 @@ static struct platform_driver usbhs_omap_driver = {
 		.owner		= THIS_MODULE,
 		.pm		= &usbhsomap_dev_pm_ops,
 	},
-	.remove		= __exit_p(usbhs_omap_remove),
+	.remove		= usbhs_omap_remove,
 };
 
 MODULE_AUTHOR("Keshava Munegowda <keshava_mgowda@ti.com>");