arm64: dts: ti: k3-am65*/j721e*: Fix unit address format error for dss node

Fix the node address to follow the device tree convention.

This fixes the dtc warning:
<stdout>: Warning (simple_bus_reg): /bus@100000/dss@04a00000: simple-bus
unit address format error, expected "4a00000"

Fixes: 76921f15 ("arm64: dts: ti: k3-j721e-main: Add DSS node")
Fixes: fc539b90 ("arm64: dts: ti: am654: Add DSS node")
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Jyri Sarha <jsarha@ti.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://lore.kernel.org/r/20201104222519.12308-1-nm@ti.com