msm: mdss: hdmi: enable scrambler during handoff

Enable scrambler during handoff scenarios in which there is no
resolution switch from the bootloader to the kernel. Furthermore,
power on the HDMI core before enabling the scrambler to ensure
that there is a smooth transition during the handoff without any
temporary blinks on the panel.

Change-Id: I94dde166dabf2b3260b6cae34bfcdf0e99fe4112
Signed-off-by: Tatenda Chipeperekwa <tatendac@codeaurora.org>