pmdomain: samsung: Rework legacy splash-screen handover workaround

pmdomain: samsung: Rework legacy splash-screen handover workaround

Limit the workaround for the lack of the proper splash-screen handover
handling to the legacy ARM 32bit systems and replace forcing a sync_state
by explicite power domain shutdown. This approach lets compiler to
optimize it out on newer ARM 64bit systems.

Suggested-by: Ulf Hansson <ulf.hansson@linaro.org>
Fixes: 0745658aebbe ("pmdomain: samsung: Fix splash-screen handover by enforcing a sync_state")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>