docs(changelog): add subsections for STM32MP25

The STM32MP2 family has 3 different types of SoCs (STM32MP25, STM32MP23
and STM32MP21). For the moment only STM32MP25 is partly supported in
TF-A. Add a dedicated subsections for STM32MP25. The other ones will be
added later. The same is done for FDTS scope.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
Change-Id: Ia18824a7b649bcd1ffa631e3aa0ecb3fd0b2d038
diff --git a/changelog.yaml b/changelog.yaml
index 3591f02..433ebee 100644
--- a/changelog.yaml
+++ b/changelog.yaml
@@ -649,6 +649,10 @@
           - title: STM32MP2
             scope: stm32mp2
 
+            subsections:
+              - title: STM32MP25
+                scope: stm32mp25
+
       - title: Texas Instruments
         scope: ti
 
@@ -1335,6 +1339,10 @@
           - title: STM32MP2
             scope: stm32mp2-fdts
 
+            subsections:
+              - title: STM32MP25
+                scope: stm32mp25-fdts
+
       - title: PIE
         scope: pie