usb_hub: fix power cycling logic

When power cycling the hub ports, a misbehaving port will prevent all ports
from being powered on because we quit at the first sign of trouble.

Skip problematic ports instead of failing the entire power on.

Cc: Marek Vasut <marex@denx.de>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>