staging: rtl8188eu: usb_intf.c: No point processing an empty table

In addition, this would globally disable HT if one device in the
system would mark it unsupported. If any device ended up requiring
this, it should be handled on a per-instance basis.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>