thunderbolt: switch: Demote a bunch of non-conformant kernel-doc headers

Fixes the following W=1 kernel build warning(s):

 drivers/thunderbolt/switch.c:730: warning: Function parameter or member 'port' not described in 'tb_init_port'
 drivers/thunderbolt/switch.c:1348: warning: Function parameter or member 'sw' not described in 'tb_plug_events_active'
 drivers/thunderbolt/switch.c:1348: warning: Function parameter or member 'active' not described in 'tb_plug_events_active'

Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Michael Jamet <michael.jamet@intel.com>
Cc: Yehezkel Bernat <YehezkelShB@gmail.com>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[ mw: Demote only static functions ]
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/switch.c

@@ -718,7 +718,7 @@ int tb_port_disable(struct tb_port *port)
 	return __tb_port_enable(port, false);
 }
 
-/**
+/*
  * tb_init_port() - initialize a port
  *
  * This is a helper method for tb_switch_alloc. Does not check or initialize
@@ -1337,7 +1337,7 @@ int tb_switch_reset(struct tb_switch *sw)
 	return res.err;
 }
 
-/**
+/*
  * tb_plug_events_active() - enable/disable plug events on a switch
  *
  * Also configures a sane plug_events_delay of 255ms.