[qcms] lut_inverse_interp16: fix black level inversion error

Inverting a TRC curve that is 0 at the origin should produce 0 at the
origin to avoid a black level error.

CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel,mac_blink_rel,win_blink_rel
BUG=504681

Review URL: https://codereview.chromium.org/1215583002

Cr-Commit-Position: refs/heads/master@{#336401}
2 files changed