usb: ehci-orion: rename error goto labels in ehci_orion_drv_probe()

In preparation to the introduction of additional initialization steps
in ehci_orion_drv_probe(), we rename the error goto labels from err1,
err2 and err3 names to some more meaningful names.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>