[DEBUG] rk3399-nanopi-neo4: SPL SD init may report -5 due to SD power-on timing

[Sune Brian]

> the vmmc-supply always on (not configurable by software) so I cannot be
> impacted by any change.

Comment on this.
The nanopi neo4 has an sd card slot and mmc slot.
The initial debug mail is only targeted on sd card.
Where the MMC do not have any issue and this is
why puzzle me at first place and yet this SD boot
issue is having trouble for a long time and not been
well investigate due to different works.

w/o reverting the regulator patch the mmc still able
to boot w/o any issue. And if I read correctly. The
NEO4 board EMMC uses main power PMIC rather
than additional power regulator [1]. So this is a huge
difference in timing and boot stability.

Brian

[1] https://wiki.friendlyelec.com/wiki/images/b/bb/NanoPi_NEO4_2008_SCH.pdf