doc: migration-guide: inform about device dependencies changes

Device dependencies are now optional, before they were always built.

Signed-off-by: Gerard Marull-Paretas <[email protected]>

doc/releases/migration-guide-3.5.rst

@@ -230,6 +230,11 @@ Required changes
 * ARM SoC initialization routines no longer need to call `NMI_INIT()`. The
   macro call has been removed as it was not doing anything useful.
 
+* Device dependencies (incorrectly referred as "device handles" in some areas)
+  are now an optional feature enabled by :kconfig:option:`CONFIG_DEVICE_DEPS`.
+  This means that an extra linker stage is no longer necessary if this option is
+  not enabled.
+
 Recommended Changes
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