OWNERS: Specify the `oem/ampere` folder for Thu Nguyen

Specify the `oem/ampere` path for Thu Nguyen from Ampere

Change-Id: I6577c6bde7ef14a2fc15fbca0ce6f30df864c750
Signed-off-by: Thu Nguyen <thu@os.amperecomputing.com>
diff --git a/OWNERS b/OWNERS
index b70ba46..0ad33ff 100644
--- a/OWNERS
+++ b/OWNERS
@@ -42,7 +42,7 @@
 - thu@os.amperecomputing.com
 
 matchers:
-- partial_regex: ampere
+- partial_regex: oem/ampere
   owners:
   - thu@os.amperecomputing.com
 - partial_regex: ibm