msm: mdss: rgb: adding rgb interface driver for qcs405

Add mdss_rgb driver to drive RGB parallel interface
required on qcs405 target. Also added an SPI controller
to transfer panel on/off sequences to RGB panel.

Change-Id: I5479a05aa9e0fbc922dabed9a4b85cec1fa167d3
Signed-off-by: Rashi Bindra <rbindra@codeaurora.org>
Signed-off-by: Narender Ankam <nankam@codeaurora.org>