arm64: dts: marvell: Rename armada-37xx USB node

No need to reflect the USB version in the node name.

Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
[gregory.clement@free-electrons.com: drop Fixes tag as it is not a bug fix.]