usb: chipidea: ehci_init_driver is intended to call one time

The ehci_init_driver is used to initialize hcd APIs for each
ehci controller driver, it is designed to be called only one time
and before driver register is called. The current design will
cause ehci_init_driver is called multiple times at probe process,
it will cause hc_driver's initialization affect current running hcd.

We run out NULL pointer dereference problem when one hcd is started
by module_init, and the other is started by otg thread at SMP platform.
The reason for this problem is ehci_init_driver will do memory copy
for current uniform hc_driver, and this memory copy will do memset (as 0)
first, so when the first hcd is running usb_add_hcd, and the second
hcd may clear the uniform hc_driver's space (at ehci_init_driver),
then the first hcd will meet NULL pointer at the same time.

See below two logs:

LOG_1:
ci_hdrc ci_hdrc.0: EHCI Host Controller
ci_hdrc ci_hdrc.0: new USB bus registered, assigned bus number 1
ci_hdrc ci_hdrc.1: does...