Split out the attachment from the generic-ehci driver

[andrew]

Summary

Create an attachment file for the existing ACPI attachment, and create a
new FDT attachment for the generic-ehci driver.

Test Plan

Boots on NanoPC-T4 (RokcChip RK3399) with GENERIC-UP. It seems to cause
a fault when SMP is enabled, however I'm unsure why.

[andrew]

sys/dev/usb/controller/generic_ehci.c

187

I'm not sure this is the best name for it, but should be ok for testing.

sys/dev/usb/controller/generic_ehci_acpi.c

78

This should probably be in a header, although it will be the only thing in the header if it's generic_ehci.h.

[manu]

This miss all the ext_resources stuff (phy, clocks) but that could be added later I guess.
Don't you need to DECLARE_CLASS and DEFINE_CLASS_0 ? (This stuff was always obscure to me ...)
Otherwise looks good for me.

sys/dev/usb/controller/generic_ehci.c

187

generic_ehci_driver ?

[val_packett.cool]

I've noticed a generic-ehci driver in sys/mips/mediatek/mtk_ehci.c already (and tried on my RK3399, it does attach). That should probably be replaced by this. Does anyone test mediatek MIPS these days? :)

[andrew]

Split out the header
Enable clocks, etc

[manu]

LGTM

sys/dev/usb/controller/generic_ehci_fdt.c

195

s/De-//