usb: musb: jz4740: Don't disable external hubs

The jz4740-musb driver does not really support OTG, so it has no reason
to disable external hubs, especially since it's a system-wide setting
and we don't want external hubs to be disabled for other USB host
controllers.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20221026182657.146630-6-paul@crapouillou.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>