dt-bindings: display/msm: expand to support MST

dt-bindings: display/msm: expand to support MST

On a vast majority of Qualcomm chipsets DisplayPort controller can
support several MST streams (up to 4x). To support MST these chipsets
use up to 4 stream pixel clocks for the DisplayPort controller and
several extra register regions. Expand corresponding region and clock
bindings for these platforms and fix example schema files to follow
updated bindings.

Note: On chipsets that support MST, the number of streams supported
can vary between controllers. For example, SA8775P supports 4 MST
streams on mdss_dp0 but only 2 streams on mdss_dp1.

Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Patchwork: https://patchwork.freedesktop.org/patch/672585/
Link: https://lore.kernel.org/r/20250903-dp_mst_bindings-v8-7-7526f0311eaa@oss.qualcomm.com