[ Upstream commit a1028dcf ]

Save pll state before dsi host is powered off. Without this change
some register values gets resetted.
Signed-off-by: Harigovindan P <harigovi@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>