The rr3_ftr function duplicates the in-kernel tracing logic, so remove
it.

This is step 1 of of removing the CONFIG_USB_DEBUG depandancy in this
driver.

Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Sean Young <sean@mess.org>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Jonathan McCrohan <jmccrohan@gmail.com>
Cc: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>