drm/msm/mdp5: Enhance operation mode for pipeline configuration

DSI and WB interfaces need a more complex pipeline configuration
than the current mdp5_ctl_set_intf().

For example, memory output connections need to be selected for
WB. Interface mode (Video vs. Command modes) also need to be
configured for DSI.

This change takes care of configuring the whole pipeline as far
as operation mode goes. DSI and WB interfaces will be added
later.

v2: rename macro to mdp5_cfg_intf_is_virtual() [pointed by Archit]

Signed-off-by: Stephane Viau <sviau@codeaurora.org>
[Remove temp bisectability hack -Rob]
Signed-off-by: Rob Clark <robdclark@gmail.com>