lib: hash: follow-up fixups for arch hash

This patch adds the include file to pull in __read_mostly on some
architectures e.g. ppc and also fixes up signatures in generic
asm.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Francesco Fusco <ffusco@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/asm-generic/hash.h

 #ifndef __ASM_GENERIC_HASH_H
 #define __ASM_GENERIC_HASH_H
 
-struct arch_hash_ops;
-static inline void setup_arch_fast_hash(struct arch_hash_ops *ops)
+struct fast_hash_ops;
+static inline void setup_arch_fast_hash(struct fast_hash_ops *ops)
 {
 }
 

lib/hash.c

@@ -12,6 +12,7 @@
 
 #include <linux/jhash.h>
 #include <linux/hash.h>
+#include <linux/cache.h>
 
 static struct fast_hash_ops arch_hash_ops __read_mostly = {
 	.hash  = jhash,