disp: msm: sde: fix qos perf for 90Hz panel

This change fixes the issue in selecting the correct
perf index for the 90Hz refresh rate, before this change
values corresponding to 60Hz were getting applied for this
refresh rate.

Change-Id: Id4f8af4da95f0d13d30f6316dc26dd65b61d7f79
Signed-off-by: Abhijit Kulkarni <kabhijit@codeaurora.org>