disp: msm: dsi: Remove unused for loop in ESD reg read validation

In ESD register read validation, a for loop is used to increment a
local variable with the length of ESD command. But this is unused
in the validation of the read data. This change removes the unused
for loop.

Change-Id: I6d1a9233061ee33a2b5390e2f922a2412af7d605
Signed-off-by: Ritesh Kumar <riteshk@codeaurora.org>