ARM: davinci: PM: support da8xx DT platforms

[ Upstream commit 7e431af8fa0b9ed9d74378c99514856211cb9db8 ]

Add PM support for DA850 device-tree boot.

Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>