ARM: dts: Remove VL805 USB node from CM4 dts

Neither the CM4 module nor the CM4IO board have a VL805 USB3
controller. The existing "usb@0,0" node is a hangover from the
Pi 4 dts; delete it. An up-to-date firmware will automatically load
the vl805 overlay on CM4s with VL805=1 in the EEPROM config, ensuring
that the firmware is notified of any PCIe reset.

See: https://forums.raspberrypi.com/viewtopic.php?t=326088



Signed-off-by: Phil Elwell <phil@raspberrypi.com>