lib: utils/fdt: Constify FDT parsing functions

Distinguish between functions which modify the devicetree and those
which only extract information from it. Other than the iterators in
fdt_domain.c, this is a mechanical conversion.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

lib/utils/fdt/fdt_pmu.c

@@ -56,7 +56,7 @@ int fdt_pmu_fixup(void *fdt)
 	return 0;
 }
 
-int fdt_pmu_setup(void *fdt)
+int fdt_pmu_setup(const void *fdt)
 {
 	int i, pmu_offset, len, result;
 	const u32 *event_val;