msm: mdss: Add support for sg_table cloning

Add support for cloning of the sg_table and
padding it with extra buffer to avoid faults
which can occur as a result of a hardware bug
that over-fetches.

Change-Id: I6f33c0568bab4f97aa6ed063bdd8b898723571d6
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Krishna Manikandan <mkrishn@codeaurora.org>