sparc64: fix sparse warning in prom_64.c

Fix following warning:
prom_64.c:376:6: warning: symbol 'arch_find_n_match_cpu_physical_id' was not declared. Should it be static?

Add missing include to pick up prototype.
Rearrange includes to use the inverse christmas tree structure.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/kernel/prom_64.c

@@ -15,11 +15,12 @@
  *      2 of the License, or (at your option) any later version.
  */
 
+#include <linux/memblock.h>
 #include <linux/kernel.h>
-#include <linux/types.h>
 #include <linux/string.h>
+#include <linux/types.h>
+#include <linux/cpu.h>
 #include <linux/mm.h>
-#include <linux/memblock.h>
 #include <linux/of.h>
 
 #include <asm/prom.h>