usb4bsd resolve conflicts
usb4bsd: Synchronise with FreeBSD r254159
usb4bsd: re-add function for rescanning the SCSI bus after attach
usb4bsd: fix a panic due to wrong locking
usb4bsd/udav sync driver with FreeBSD
Sync ehci.c with FreeBSD
Sync ehci.h with FreeBSD
Sync ehci_pci.c with FreeBSD
Sync ohci code with FreeBSD
Sync uhci with FreeBSD
Sync xhci with FreeBSD
Sync with FreeBSD
Add another controller to ohci_pci.c
Add usb_dragonfly.h for DragonFly specific configuration
Sync sys/bus/u4b/* with FreeBSD
Use sys/bus/u4b/usb_dragonfly.h
Fix some spillage from the sync
Fix some minor compilation issues after sync

The u4b core is now at FreeBSD r241689