doc: release-notes-2.7: Added CAN release notes

This commit adds the CAN specific release-notes for the 2.7
release.

Signed-off-by: Alexander Wachter <[email protected]>

Author: alexanderwachter

doc/releases/release-notes-2.7.rst

@@ -344,6 +344,8 @@ Drivers and Sensors
 
 * CAN
 
+  * Renesas R-Car driver added
+
 
 * Clock Control