msm: mdss: hdmi: finetune CEC_REFTIMER:REFTIMER

CEC Read and Write protocol and state machine uses 50us pulse
to ensure the CEC signaling adheres to the relatively slow protocol.
The reftimer to generate 50us is configured using
CEC_REFTIMER:REFTIMER.
Current value of REFTIMER is not properly configured to generate
50us pulse.
Finetune CEC_REFTIMER:REFTIMER from current value to slightly
higher value to generate 51us to ensure CEC Read and Write
logic are working properly without any CEC line errors.

Change-Id: I57e3f8e8197763b2a2c910b12705c232ad8eb1a8
Signed-off-by: Narender Ankam <nankam@codeaurora.org>