Disable external hubs

configname: CONFIG_USB_OTG_BLACKLIST_HUB

Linux Kernel Configuration
└─>Device Drivers
└─>USB support
└─>Disable external hubs
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
If you say Y here, then Linux will refuse to enumerate
external hubs. OTG hosts are allowed to reduce hardware
and software costs by not supporting external hubs. So
are "Emedded Hosts" that don't offer OTG support.

depends
CONFIG_USB_SUPPORT
CONFIG_EMBEDDED or CONFIG_USB_OTG

is selected by
CONFIG_USB_MUSB_JZ4740