of/fdt: convert initial_boot_params to opaque pointer

Now that all accesses to FDT header data has been converted to accessor
helpers, initial_boot_params can become an opaque pointer.

Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Stephen Chivers <schivers@csc.com>
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index e10099c9..1f882e1 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -78,7 +78,7 @@
 /* TBD: Temporary export of fdt globals - remove when code fully merged */
 extern int __initdata dt_root_addr_cells;
 extern int __initdata dt_root_size_cells;
-extern struct boot_param_header *initial_boot_params;
+extern void *initial_boot_params;
 
 extern char __dtb_start[];
 extern char __dtb_end[];