Revert "arm: dts: rockchip: radxa-cm3-io, rock-3a: enable regulators for usb"

Remove regulator-boot-on prop from regulators now that the phy core has
support for phy-supply after the commit c57e0dcd ("phy: add support
for phy-supply").

This reverts commit 7911f409.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>