west.yml: hal_stm32: Don't include legacy headers anymore

We're not supposed to rely on symbols provided by these files.
In case it is required stm32 zephyr code base should be updated rather
than relying on legacy definitions.

Additionally:
Fixes zephyrproject-rtos#70136

Signed-off-by: Erwan Gouriou <erwan.gouriou@st.com>

west.yml

@@ -229,7 +229,7 @@ manifest:
       groups:
         - hal
     - name: hal_stm32
-      revision: 366c5c909fbcecf94f32411887132024f61b0bcd
+      revision: pull/209/head
       path: modules/hal/stm32
       groups:
         - hal