msm: mdss: Sanitize post processing inputs

Sanitize the inputs to histogram, assertive display, and calibration buffer
so that invalid values cannot be used as feature configuration.

CRs-Fixed: 516710
Change-Id: Ifb585174b1baadbac628f53fe67f3c3b3ae61a54
Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>