physmem: Move the ram0 device earlier in the boot

[andrew]

Summary

If the ram driver is unable to reserve a memory range it will panic
with no real information why. Move this driver earlier in the boot so
any devices that cause the conflict will fail to attach.

This should make it easier to debug why the conflict exists.

Sponsored by: Arm Ltd

[mhorne]

Yes, this is smarter.

I kind of regret adding this thing. Although it is conceptually helpful/correct, its positive practical impact has so far been zero, while it has created several headaches.

[kevans]

In D48766#1112402, @mhorne wrote:

Yes, this is smarter.

I kind of regret adding this thing. Although it is conceptually helpful/correct, its positive practical impact has so far been zero, while it has created several headaches.

Meh, it'll turn its life around- more failure to attach because of it rather than panicking will trend it back towards positive practical impact and fewer headaches, and it's a pretty small diff to get there.