x86/pci: Add cap_resource()

Prepare for 32bit pci root bus

-v2: hpa said we should compare with (resource_size_t)~0
-v3: according to Linus to use MAX_RESOURCE instead.
     also need need to put related patches together
-v4: according to Andrew, use min in cap_resource()

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-8-git-send-email-yinghai@kernel.org>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

include/linux/range.h

@@ -19,4 +19,12 @@ int clean_sort_range(struct range *range, int az);
 
 void sort_range(struct range *range, int nr_range);
 
+#define MAX_RESOURCE ((resource_size_t)~0)
+static inline resource_size_t cap_resource(u64 val)
+{
+	if (val > MAX_RESOURCE)
+		return MAX_RESOURCE;
+
+	return val;
+}
 #endif