x86: Move table csum into separate header

We need the checksum function without all the other table functionality
soon, so let's split it out into its own header file.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/x86/include/asm/tables.h

@@ -7,6 +7,8 @@
 #ifndef _X86_TABLES_H_
 #define _X86_TABLES_H_
 
+#include <tables_csum.h>
+
 /*
  * All x86 tables happen to like the address range from 0xf0000 to 0x100000.
  * We use 0xf0000 as the starting address to store those tables, including

arch/x86/lib/tables.c

@@ -38,18 +38,6 @@ static table_write table_write_funcs[] = {
 #endif
 };
 
-u8 table_compute_checksum(void *v, int len)
-{
-	u8 *bytes = v;
-	u8 checksum = 0;
-	int i;
-
-	for (i = 0; i < len; i++)
-		checksum -= bytes[i];
-
-	return checksum;
-}
-
 void table_fill_string(char *dest, const char *src, size_t n, char pad)
 {
 	int start, len;

include/tables_csum.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _TABLES_CSUM_H_
+#define _TABLES_CSUM_H_
+
+static inline u8 table_compute_checksum(void *v, int len)
+{
+	u8 *bytes = v;
+	u8 checksum = 0;
+	int i;
+
+	for (i = 0; i < len; i++)
+		checksum -= bytes[i];
+
+	return checksum;
+}
+
+#endif