MAINTAINERS: add tests to intel ADSP area

add missing tests to the intel ADSP area.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/MAINTAINERS.yml b/MAINTAINERS.yml
index 5796b98..c6acf1d 100644
--- a/MAINTAINERS.yml
+++ b/MAINTAINERS.yml
@@ -1733,6 +1733,7 @@
     - boards/xtensa/intel_*/
     - soc/xtensa/intel_*/
     - dts/xtensa/intel/
+    - tests/boards/intel_adsp/
   labels:
     - "platform: Intel ADSP"