arm64: fix endianness annotation in get_kaslr_seed()

In the flattened device tree format, all integer properties are
in big-endian order.
Here the property "kaslr-seed" is read from the fdt and then
correctly converted to native order (via fdt64_to_cpu()) but the
pointer used for this is not annotated as being for big-endian.

Fix this by declaring the pointer as fdt64_t instead of u64
(fdt64_t being itself typedefed to __be64).
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/kernel/kaslr.c

@@ -27,7 +27,7 @@ u16 __initdata memstart_offset_seed;
 static __init u64 get_kaslr_seed(void *fdt)
 {
 	int node, len;
-	u64 *prop;
+	fdt64_t *prop;
 	u64 ret;
 
 	node = fdt_path_offset(fdt, "/chosen");