UPSTREAM: pwm: rockchip: Add support for atomic update

UPSTREAM: pwm: rockchip: Add support for atomic update

Implement the ->apply() function to add support for atomic update.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
(commit 2bf1c98aa5a41651f5e6455117ff06f66ff3cc50)

Conflicts:
	drivers/pwm/pwm-rockchip.c

Change-Id: I92745cf301c26d20da284da8234e244828598d52
Signed-off-by: David Wu <david.wu@rock-chips.com>