docs: releases: 4.4: Add entry for DT_CHILD_BY_UNIT_ADDR

Add a DeviceTree section and entries for the new C macros.

Signed-off-by: Pieter De Gendt <pieter.degendt@basalte.be>

Author: pdgendt

doc/releases/release-notes-4.4.rst

@@ -96,6 +96,11 @@ New Samples
   Same as above, this will also be recomputed at the time of the release.
  Just link the sample, further details go in the sample documentation itself.
 
+DeviceTree
+**********
+
+* :c:macro:`DT_CHILD_BY_UNIT_ADDR`
+* :c:macro:`DT_INST_CHILD_BY_UNIT_ADDR`
 
 Libraries / Subsystems
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