msm: mdss: do not turn off interface clocks for doze mode

When entering doze mode, do not turn off the interface clocks since
display updates are expected in this mode. This also avoid unnecessary
delays when entering doze mode while trying to wait for the clocks to be
turned off.

Change-Id: Ie6658a561f5d49aff50881c561fef858f3d26c61
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>