drm/msm/sde: add line insertion support for sspp

Add line insertion support for sspp, this is used to support
display with external splitter. Also extend sspp feature bits
from 32 to 64 as line insertion feature index is 32.

Change-Id: Ifa4f2b2914f391ced42383282731a62cf1ad82ee
Signed-off-by: Xiaowen Wu <wxiaowen@codeaurora.org>