drm/msm/sde: remove out of bound access for qos lut parsing

QOS LUT dtsi entries use existing hardware parsing APIs
but dos not increase the size of array. This causes out of
bound access while reading u32 lut array entry. This patch
fixes the array size and also adds checks to avoid future
out of bound access. It also fixes the memory leak in
qos lut parsing.

Change-Id: I98de052d03e1bcfd79d15ab99ca41d7782e56682
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>