ext4_utils: fix build for 64 bit

Correct u64/s64 definitions
Use PRIu64 to print u64

Change-Id: Icaf7998946b0a2faa03495b404af8b94e4e3d047
diff --git a/ext4_utils/ext4_utils.h b/ext4_utils/ext4_utils.h
index 9b5b7c4..447d416 100644
--- a/ext4_utils/ext4_utils.h
+++ b/ext4_utils/ext4_utils.h
@@ -70,8 +70,13 @@
 #define le32_to_cpu(x) (x)
 #define le16_to_cpu(x) (x)
 
+#ifdef __LP64__
+typedef unsigned long u64;
+typedef signed long s64;
+#else
 typedef unsigned long long u64;
 typedef signed long long s64;
+#endif
 typedef unsigned int u32;
 typedef unsigned short int u16;
 typedef unsigned char u8;