drm/msm/sde: fix smartDMA programming

This change fixes the following issues when an SDE plane
is programmed in smartDMA mode:

	- On programming a HW pipe in multirect mode,
	QSEED block will by bypassed. Still alpha and
	bitwidth of the QSEED need to be updated for
	RECT0 path.

	- With PD_MEM split into half in parallel fetch
	mode, each RECT can support up to full SSPP width
	if programmed with linear format buffers as they
	require only 2 lines of buffering. But with tiled
	format buffers, each RECT can support half the
	width as they require 5 lines of buffering.

	- If both the RECT's share the same register for
	programming a field, clear the respective register
	bits when not in use.

Change-Id: I9ea77e0f9bc5dbc94ffe5e5a6bea0ebe35df5a74
Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>