USB: musb_gadget: fix kernel oops in txstate()

Commit 7723de7e (USB: musb_gadget: remove
pointless loop) included uncalled for (and incorrect) optimization that
might cause a kernel oops in txstate() -- undo it.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>