msm: mdss: fix crash in mdp probe with continuous splash disabled

Reading the default panic LUTs after disabling the splash clks in mdp
probe when continuous splash is disabled in lk causes the crash. This
change disables the splash clks after reading the panic LUTs.

Change-Id: I8fc4ed0f515a3b657a40cd430150353ffb90db35
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>