migration-guides: remove SERIAL_CONSOLES_CHECK

(From yocto-docs rev: 364f8c17ba380107b2d837e17403307c3e04477c)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Reviewed-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/migration-guides/migration-4.3.rst

@@ -130,6 +130,9 @@ The following variables have been removed:
 -  ``PERLARCH``
 -  ``PERLVERSION``
 -  ``QEMU_USE_SLIRP``
+-  ``SERIAL_CONSOLES_CHECK``, which is no longer necessary because all
+   consoles listed in :term:`SERIAL_CONSOLES` are checked for their existence
+   before a ``getty`` is started.
 
 .. _migration-4.3-removed-recipes:
 

documentation/migration-guides/release-notes-4.3.rst

@@ -92,7 +92,8 @@ New Features / Enhancements in 4.3
 
    -  `ttyrun <https://github.com/ibm-s390-linux/s390-tools>`__, starts
       ``getty`` programs only when a terminal exists, preventing respawns
-      through the ``init`` program.
+      through the ``init`` program. This allowed to remove the
+      ``SERIAL_CONSOLES_CHECK`` variable.
 
 -  New classes: