arm64: zynqmp: Start usb automatically via preboot on Kria

arm64: zynqmp: Start usb automatically via preboot on Kria

U-Boot configures the USB config object which enables power for
the IP, without this the linux usb driver won't work.
So add "usb start" as part of preboot command.

Fixes: dd4a82201694 ("arm64: zynqmp: Introduce kria SOM defconfig")
Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/180c9776b03d57d8218d161924363906ef354394.1744272843.git.michal.simek@amd.com