arm64: dts: ti: k3-am654: Fix wakeup_uart reg address

cbass_wakeup interconnect which is the parent of wakeup_uart node
defines address-cells=1 and size-cells=1, therefore fix up reg property
of wakeup_uart node accordingly. Otherwise, this UART instance fails to
probe if enabled.

Fixes: 4201af25

 ("arm64: dts: ti: am654: Add uart nodes")
Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>