drm/bridge: cdns-dsi: Use pre_enable/post_disable to enable/disable

The cdns-dsi controller requires that it be turned on completely before
the input DPI's source has begun streaming[0]. Not having that, allows
for a small window before cdns-dsi enable and after cdns-dsi disable
where the previous entity (in this case tidss's videoport) to continue
streaming DPI video signals. This small window where cdns-dsi is
disabled but is still receiving signals causes the input FIFO of
cdns-dsi to get corrupted. This causes the colors to shift on the output
display. The colors can either shift by one color component (R->G, G->B,
B->R), or by two color components (R->B, G->R, B->G).

Since tidss's videoport starts streaming via crtc enable hooks, we need
cdns-dsi to be up and running before that. Now that the bridges are
pre_enabled before crtc is enabled, and post_disabled after crtc is
disabled, use the pre_enable and post_disable hooks to get cdns-dsi
ready and running before the tidss videoport to get pass the color shift
issues.

[0]: See section 12.6.5.7.3 "Start-up Procedure" in J721E SoC TRM
     TRM Link: http://www.ti.com/lit/pdf/spruil1

Reviewed-by: Tomi Valkeinen <[email protected]>
Tested-by: Tomi Valkeinen <[email protected]>
Signed-off-by: Aradhya Bhatia <[email protected]>
Signed-off-by: Aradhya Bhatia <[email protected]>
Tested-by: Devarsh Thakkar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Maxime Ripard <[email protected]>

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