sparc: Create common header file for prom_{32,64}.c

This is where common declarations will go as we unify
these files as much as possible into common code.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/kernel/prom_64.c b/arch/sparc/kernel/prom_64.c
index dbba82f..651448d 100644
--- a/arch/sparc/kernel/prom_64.c
+++ b/arch/sparc/kernel/prom_64.c
@@ -30,9 +30,7 @@
 #include <asm/upa.h>
 #include <asm/smp.h>
 
-extern struct device_node *allnodes;	/* temporary while merging */
-
-extern rwlock_t devtree_lock;	/* temporary while merging */
+#include "prom.h"
 
 struct device_node *of_find_node_by_phandle(phandle handle)
 {