usb: musb: core: set has_tt flag

MUSB is a non-standard host implementation which
can handle all speeds with the same core. We need
to set has_tt flag after commit
d199c96d (USB: prevent
buggy hubs from crashing the USB stack) in order for
MUSB HCD to continue working.

Signed-off-by: Felipe Balbi <balbi@ti.com>
Cc: stable <stable@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Michael Jones <michael.jones@matrix-vision.de>
Tested-by: Alexander Holler <holler@ahsoftware.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>