[nrf fromtree] doc: release-notes 3.3: Update MCUmgr transport note

Corrects a note on the revamped bluetooth transport registration.

Signed-off-by: Jamie McCrae <[email protected]>
(cherry picked from commit 6512400)

Author: nordicjm

doc/releases/release-notes-3.3.rst

@@ -64,15 +64,10 @@ Changes in this release
 
 * MCUmgr Bluetooth and UDP transports no longer need to be registered by the
   application code, these will now automatically be registered at bootup (this
-  feature can be disabled or tweaked by adjusting:
-  :kconfig:option:`CONFIG_MCUMGR_TRANSPORT_BT_AUTOMATIC_INIT`,
-  :kconfig:option:`CONFIG_MCUMGR_TRANSPORT_BT_AUTOMATIC_INIT_WAIT`, and
-  :kconfig:option:`CONFIG_MCUMGR_TRANSPORT_UDP_AUTOMATIC_INIT`. If applications
-  register transports then those registrations should be removed to prevent
-  registering the same transport multiple times. If the Bluetooth stack needs
-  to be setup/initialised by another module or the application itself, then
-  :kconfig:option:`CONFIG_MCUMGR_TRANSPORT_BT_AUTOMATIC_INIT` should be
-  disabled and the application should call :c:func:`smp_bt_start` at startup.
+  feature can be disabled for the UDP transport by setting
+  :kconfig:option:`CONFIG_MCUMGR_TRANSPORT_UDP_AUTOMATIC_INIT`). If
+  applications register transports then those registrations should be removed
+  to prevent registering the same transport multiple times.
 
 Removed APIs in this release
 ============================