msm: mdss: fix simulator panel SW-TE parameters

In simulator panel SW-TE approach, we rely on the sync config
height, init, start_pos and read ptr TE parameters. Set start_pos,
init and read ptr with respect to panel yres, as it is done in
the default settings when it is used with an actual panel.
Setting these parameters with respect to 0 causes fps drops.

Change-Id: I9acf4d1558767e7789a5e37dc2444f947d11eb21
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>