rockchip: rk3288 re-rfactor  pwm driver

Both SOCs use the same pwm controller.

With this patch in place it is easy to add support for 3399.

BRANCH=none
BUG=none
TEST=booted veyron_jerry to kernel login prompt

Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Change-Id: I79428f9ec71017ad8f3ad67dac1468178ccc3a1e
Reviewed-on: https://chromium-review.googlesource.com/338019
Reviewed-by: Julius Werner <jwerner@chromium.org>
4 files changed