[U-Boot] [RFC] dm: tegra: boot time regression

[Marcel Ziswiler]

Migrating our BSPs towards mainline U-Boot I noticed it suddenly booting
slower. With mainline Linux I noticed about a 1 to 2 second increase
while booting downstream L4T takes 10 to 15 seconds longer! Git
bisecting it revealed the following commit to be at odds:

858530a8c0a7ce7e573e513934804a00d6676813
dm: tegra: Enable driver model for serial

Switching back to not using the DM driver for serial brings it back to
booting much faster. However looking closely at the serial stuff and its
accompanying settings I could not quite pinpoint why exactly any of this
would make the Linux kernel suddenly boot slower.

Has anybody noticed similar issues?