doc: migration-guide-4.1: add note about nxp,kinetis-ftm change

Add note about nxp,kinetis-ftm binding changes.

Signed-off-by: Manuel Argüelles <[email protected]>

Author: manuargue

doc/releases/migration-guide-4.1.rst

@@ -234,6 +234,12 @@ RTC
 
 * Renamed the ``compatible`` from ``nxp,kinetis-rtc`` to :dtcompatible:`nxp,rtc`.
 
+Timer
+=====
+
+* Renamed the ``compatible`` from ``nxp,kinetis-ftm`` to :dtcompatible:`nxp,ftm` and relocate it
+  under ``dts/bindings/timer``.
+
 Video
 =====