thunderbolt: Prefix CL state related log messages with "CLx: "

This makes it easier to spot from the logs and follows what we do with
the TMU code already. We also log enabling/disabling CL states using the
tb_sw_dbg() instead of tb_port_dbg().

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>