msm: mdss: Fix dual-DSI mixer swap

In dual-DSI panel configuration it is possible that panels are physically
swapped on the device. In those situations mixer swap is done. There is
an old dead code in current implementation which leads to failures in
mixer swap use-case. Fix these failures by removing this dead code.

Change-Id: Ib0d7141e322f18bcf1060bc5ab2a404dc41a4cc2
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>
msm: mdss: Enable FBC on Layer mixer 1

Layer mixer 1 also supports framebuffer compression. This is
needed to support dual-dsi fbc enabled panels.

Change-Id: I1118298e89ce06ef14bbea1c47478f04e3050154
Signed-off-by: Siddhartha Agrawal <agrawals@codeaurora.org>
msm: mdss: modify dual-dsi interface swap implementation

In certain dual-dsi products it is possible to physically attach
left-panel on DSI1 interface and right-panel on DSI0 interface. This
particular configuration requires MDSS to swap its output going into
these two interfaces. Current implementation achieves this by swapping
pipes across two layer mixers (LMs) but that solution is not scalable
and optimum when used with source split. We can achieve the same results
by using crossbar located before MDSS interfaces which will allow ctl0
to send data to DSI1 and ctl1 to DSI0. This new implementation is
minimalist and scalable. Implement this new method by swapping interface
assigned to ctl path.

CRs-Fixed: 651286
Change-Id: I7a435f81bd42c197e2eb8655882da9352c091c09
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>

Conflicts:
	drivers/video/msm/mdss/mdss_mdp_ctl.c