doc: release: 2.7: remove duplicate IPM entry

Remove duplicate IPM entry.

Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>
diff --git a/doc/releases/release-notes-2.7.rst b/doc/releases/release-notes-2.7.rst
index 5ac5dc2..e1f1010 100644
--- a/doc/releases/release-notes-2.7.rst
+++ b/doc/releases/release-notes-2.7.rst
@@ -433,15 +433,11 @@
 
 * IPM
 
-  * Added STM32 HSEM IPM driver.
+  * STM32: Add HSEM based IPM driver for STM32H7 series
 
 * Interrupt Controller
 
 
-* IPM
-
-  * STM32: Add HSEM based IPM driver for STM32H7 series
-
 * LED