arm64: dts: ti: k3-am654-base-board: Fix up un-necessary status set to "okay" for USB

The default state of a device tree node is "okay". There is no specific
use of explicitly adding status = "okay" in the board dts.

Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Acked-by: Roger Quadros <rogerq@ti.com>
Cc: Roger Quadros <rogerq@ti.com>
Link: https://lore.kernel.org/r/20201113211826.13087-5-nm@ti.com