mx8qx_colibri: 8dx lpddr4 cbt enablement

mx8qx_colibri: 8dx lpddr4 cbt enablement

Finally, do i.MX 8DX LPDDR4 Command Bus Training (CBT) enablement after
NXP fixed their side of things in the SCFW 1.2.5.

Note: While at it also fix an 8QXP comment indentation.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>