ANDROID: GKI: power_supply: Add operating frequency property

Signed-off-by: Patrick Tjin <pattjin@google.com>
Bug: 127374126
(cherry picked from commit e0bb03882c146ce9676430296e3239bdad42c3a0)
Signed-off-by: Thierry Strudel <tstrudel@google.com>
(cherry picked from commit 99b6e1d28b835dab8d870742f53a94a628d61a47)
Signed-off-by: Mark Salyzyn <salyzyn@google.com>
Bug: 150789066
Change-Id: I9d8ce5c6bea6c5b98549ea659f4ec22170041a90