usb: musb: fix error return code in omap2430_probe()

Before calling platform_get_resource() in omap2430_probe(), the 'ret' is
re-assgined to 0, it can't return an error code, if platform_get_resource
fails. Set the error code to -EINVAL to fix this.

Fixes: ffbe2fea

 ("usb: musb: omap2430: Fix probe regression for missing resources")
Cc: stable <stable@kernel.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221230081730.1655616-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>