x86: Move range related operation to one file

We have almost the same code for mtrr cleanup and amd_bus checkup, and
this code  will also be used in replacing bootmem with early_res,
so try to move them together and reuse it from different parts.

Also rename update_range to subtract_range as that is what the
function is actually doing.

-v2: update comments as Christoph requested

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-4-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/include/linux/range.h b/include/linux/range.h
new file mode 100644
index 0000000..0789f14
--- /dev/null
+++ b/include/linux/range.h
@@ -0,0 +1,22 @@
+#ifndef _LINUX_RANGE_H
+#define _LINUX_RANGE_H
+
+struct range {
+	u64   start;
+	u64   end;
+};
+
+int add_range(struct range *range, int az, int nr_range,
+		u64 start, u64 end);
+
+
+int add_range_with_merge(struct range *range, int az, int nr_range,
+				u64 start, u64 end);
+
+void subtract_range(struct range *range, int az, u64 start, u64 end);
+
+int clean_sort_range(struct range *range, int az);
+
+void sort_range(struct range *range, int nr_range);
+
+#endif