riscv: dts: microchip: fix memory node unit address for icicle

Evidently I forgot to update the unit address for the 38-bit cached
memory node when I changed the address in the reg property..
Update it to match.

Fixes: 6c119330 ("riscv: dts: microchip: update memory configuration for v2022.10")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>