usb: onboard-hub: Fix the return values of regulator APIs

Don't error out if there is no vdd regulator supply, as these are
optional properties.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Reviewed-by: Marek Vasut <marex@denx.de>
1 file changed