ARM: dts: Add rotator OT limit optional DT property

This property can be used to dynamically change writeback
path OT. Based on different targets this can be tuned to
meet performance requirements.

Change-Id: Ibe39ae8ae9d8697477a3734cc26e078e74e56cc8
Signed-off-by: Jayant Shekhar <jshekhar@codeaurora.org>