To have a working display through DPI, a workaround has been
implemented downstream to add "mm_dpi0_dpi0" and "dpi0_sel" to
the DPI node. Shortly, that add an extra clock.
It seems consistent to have the "dpi0_sel" as parent.
Additionnaly, "vpll_dpix" isn't used/managed.
Then, set the "mm_dpi0_dpi0" parent clock to "dpi0_sel".