dts: arm: st: stm32wba: include <mem.h> from series' root DTSI

Include <mem.h> from the series' root DTSI file and remove inclusion of
the file from other levels since it becomes redundant. This avoids the
current situation where the same #include directive is duplicated among
many files, and where the file is sometimes included multiple times when
walking up the inclusion chain up until the root DTSI file.

Signed-off-by: Mathieu Choplain <mathieu.choplain-ext@st.com>
diff --git a/dts/arm/st/wba/stm32wba.dtsi b/dts/arm/st/wba/stm32wba.dtsi
index 2a543b0..2f04f92 100644
--- a/dts/arm/st/wba/stm32wba.dtsi
+++ b/dts/arm/st/wba/stm32wba.dtsi
@@ -16,6 +16,7 @@
 #include <zephyr/dt-bindings/dma/stm32_dma.h>
 #include <zephyr/dt-bindings/power/stm32_pwr.h>
 #include <freq.h>
+#include <mem.h>
 
 / {
 	chosen {
diff --git a/dts/arm/st/wba/stm32wba52Xg.dtsi b/dts/arm/st/wba/stm32wba52Xg.dtsi
index ecae645..e32ede0 100644
--- a/dts/arm/st/wba/stm32wba52Xg.dtsi
+++ b/dts/arm/st/wba/stm32wba52Xg.dtsi
@@ -3,7 +3,6 @@
  *
  * SPDX-License-Identifier: Apache-2.0
  */
-#include <mem.h>
 #include <st/wba/stm32wba52.dtsi>
 
 / {
diff --git a/dts/arm/st/wba/stm32wba55Xg.dtsi b/dts/arm/st/wba/stm32wba55Xg.dtsi
index f5c23f0..26b4484 100644
--- a/dts/arm/st/wba/stm32wba55Xg.dtsi
+++ b/dts/arm/st/wba/stm32wba55Xg.dtsi
@@ -3,7 +3,6 @@
  *
  * SPDX-License-Identifier: Apache-2.0
  */
-#include <mem.h>
 #include <st/wba/stm32wba55.dtsi>
 
 / {
diff --git a/dts/arm/st/wba/stm32wba65Xi.dtsi b/dts/arm/st/wba/stm32wba65Xi.dtsi
index 422ae59..c348c81 100644
--- a/dts/arm/st/wba/stm32wba65Xi.dtsi
+++ b/dts/arm/st/wba/stm32wba65Xi.dtsi
@@ -3,7 +3,6 @@
  *
  * SPDX-License-Identifier: Apache-2.0
  */
-#include <mem.h>
 #include <st/wba/stm32wba65.dtsi>
 
 / {