drm/rockchip: Restore psr->state when enable/disable psr failed

If we failed disable psr, it would hang the display until next psr
cycle coming. So we should restore psr->state when it failed.

Cc: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: zain wang <wzz@rock-chips.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180423105003.9004-14-enric.balletbo@collabora.com