drm: exynos: dsi: Switch to atomic funcs

The new support drm bridges are moving towards atomic functions.

Replace atomic version of functions to continue the transition
to the atomic API.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220303163654.3381470-7-jagan@amarulasolutions.com