ext4: consolidate in_range() definitions

There are duplicate macro definitions of in_range() in mballoc.h and
balloc.c.  This consolidates these two definitions into ext4.h, and
changes extents.c to use in_range() as well.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger@sun.com>

fs/ext4/ext4.h

@@ -1819,6 +1819,8 @@ static inline void set_bitmap_uptodate(struct buffer_head *bh)
 	set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state);
 }
 
+#define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)
+
 #endif	/* __KERNEL__ */
 
 #endif	/* _EXT4_H */