Add Ownership to powerhint files

Bug: 248115959
Signed-off-by: Taeju Park <taeju@google.com>
Change-Id: I3a921c6d09bbf116df0674da1f83efa8a9d90a22

OWNERS

diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..1451bd8
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1 @@
+per-file powerhint.json = jychen@google.com,jenhaochen@google.com,wvw@google.com,joaodias@google.com