boards: nordic: Rearrange ram0x regions.

The ram0x partitions seem to be not compliant with nRF54H20
architecture and it causes that in the application dts overlay file
it is difficult to extend cpuapp_ram0x_region without modifying
whole layout.

It is better to place cpurad_ram0x_region at the beginning at
2f010000 address and then cpuapp_ram0x_region right after that.
Thanks to that, if the application needs to have more than 256 kB
of RAM, in the application dts overlay file, a user can increase
cpuapp_ram0x_region size up to 2f0be000.

Signed-off-by: Arkadiusz Balys <arkadiusz.balys@nordicsemi.no>