[nrf fromtree] samples: drivers: jesd216: Run sample on nrf54lm20b

Add overlay that defines DTS nodes required to run
the jesd216 sample on nrf54lm20b target.

Signed-off-by: Sebastian Głąb <sebastian.glab@nordicsemi.no>
(cherry picked from commit 8b5b7e6bc8472818498e1aa8439d1c8a8116ba4c)

Author: nordic-segl

samples/drivers/jesd216/boards/nrf54lm20dk_nrf54lm20b_cpuapp.overlay

@@ -0,0 +1,9 @@
+/*
+ * Copyright (c) 2026 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&mx25r64 {
+	status = "okay";
+};

samples/drivers/jesd216/sample.yaml

@@ -22,6 +22,7 @@ tests:
       - mimxrt1170_evk/mimxrt1176/cm7
       - mimxrt1170_evk/mimxrt1176/cm4
       - nrf54lm20dk/nrf54lm20a/cpuapp
+      - nrf54lm20dk/nrf54lm20b/cpuapp
     filter: dt_compat_enabled("jedec,spi-nor") or dt_compat_enabled("jedec,mspi-nor")
     depends_on: spi
   sample.drivers.jesd216.nrf52840dk_spi:
@@ -36,6 +37,7 @@ tests:
       - nrf54l15dk/nrf54l10/cpuapp
       - nrf54l15dk/nrf54l05/cpuapp
       - nrf54lm20dk/nrf54lm20a/cpuapp
+      - nrf54lm20dk/nrf54lm20b/cpuapp
     integration_platforms:
       - nrf54lm20dk/nrf54lm20a/cpuapp
     harness_config: