msm: mdss: fix the non-continuous splash screen use case

In the non-continuous splash screen use case, we need to
stop the display.  The display clocks are on before we
stop the display.

Change-Id: If8f76d4776fb64f4deb89e5b78c52ab54a56f02a
Signed-off-by: Xiaoming Zhou <zhoux@codeaurora.org>