of/fdt: update of_get_flat_dt_prop in prep for libfdt

Make of_get_flat_dt_prop arguments compatible with libfdt fdt_getprop
call in preparation to convert FDT code to use libfdt. Make the return
value const and the property length ptr type an int.

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 991ec74..b36a50d 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -66,7 +66,7 @@
 extern void *of_fdt_get_property(struct boot_param_header *blob,
 				 unsigned long node,
 				 const char *name,
-				 unsigned long *size);
+				 int *size);
 extern int of_fdt_is_compatible(struct boot_param_header *blob,
 				unsigned long node,
 				const char *compat);
@@ -88,8 +88,8 @@
 extern int of_scan_flat_dt(int (*it)(unsigned long node, const char *uname,
 				     int depth, void *data),
 			   void *data);
-extern void *of_get_flat_dt_prop(unsigned long node, const char *name,
-				 unsigned long *size);
+extern const void *of_get_flat_dt_prop(unsigned long node, const char *name,
+				       int *size);
 extern int of_flat_dt_is_compatible(unsigned long node, const char *name);
 extern int of_flat_dt_match(unsigned long node, const char *const *matches);
 extern unsigned long of_get_flat_dt_root(void);
@@ -103,7 +103,7 @@
 extern int early_init_dt_reserve_memory_arch(phys_addr_t base, phys_addr_t size,
 					     bool no_map);
 extern void * early_init_dt_alloc_memory_arch(u64 size, u64 align);
-extern u64 dt_mem_next_cell(int s, __be32 **cellp);
+extern u64 dt_mem_next_cell(int s, const __be32 **cellp);
 
 /* Early flat tree scan hooks */
 extern int early_init_dt_scan_root(unsigned long node, const char *uname,