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

Add note about compatible change for nxp,kinetis-dspi.

Signed-off-by: Manuel Argüelles <manuel.arguelles@nxp.com>

Author: manuargue

doc/releases/migration-guide-4.1.rst

@@ -187,6 +187,7 @@ SPI
 ===
 
 * Renamed the ``compatible`` from ``nxp,imx-lpspi`` to :dtcompatible:`nxp,lpspi`.
+* Renamed the ``compatible`` from ``nxp,kinetis-dspi`` to :dtcompatible:`nxp,dspi`.
 
 Regulator
 =========