Several of these override functions access the FDT blob. Explicitly
indicate which callbacks are allowed to modify the FDT blob by passing
the parameter as a possibly-const pointer. This also reduces code size
by deduplicating the call to fdt_get_address().
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
