msm: mdss: Balance mdp and dsi clocks for command mode panels

MDP clocks are not balanced for command mode panels with continuous
splash screen turned on. Need to turn both mdp and dsi clk off when
splash screen is done.

CRs-fixed: 486155
Change-Id: I95d2efbc6c5d9a7b074f7e6c0abf66d062a090de
Signed-off-by: Siddhartha Agrawal <agrawals@codeaurora.org>
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>