Revert: "dt-bindings: add documentation for sde-limit"

This reverts commit 658f1491b962fceccb622a9ba78e74af3c1fc0f0
from msm-4.19 which was ported as part of the display device
tree techpack.

Support for sde-limits has been removed from the driver as it's
no longer needed. BW limits have moved to per target based XML
files in user-space and linewidth limits already have other
properties for specifying.

Change-Id: Idcbe8e10e94785bc5774a94e2326d2f77ce4b5ac