arm: dts: k3-am625-beagleplay-u-boot: drop duplicate bootph-nodes

Kernel dts import now provides bootph-all and bootph-pre-ram properties
for the properties we have been overriding so far. Drop the same.

Reviewed-by: Dhruva Gole <d-gole@ti.com>
Tested-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>