Use dev_remap_addr() which supports both live device tree and flat DT backends, avoiding direct dependency on devfdt_* helpers. And only mapping sizeof(void *) is wrong, RNG_FIFO_COUNT_OFFSET(0x24) is accessed in this driver. So dev_remap_addr() could also fix the mapping size. No functional changes. Signed-off-by: Peng Fan <peng.fan@nxp.com>