arm64: dts: ti: k3-j721e: Correct the address for MAIN NAVSS

On am654 the MAIN NAVSS base address was 0x30800000, but in j721e it is
at 0x30000000

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>