TAKE - more efficient bit searching function

[Steve Lord <lord@xxxxxxx>]

>From kernel profiling this function was a dog, using a more efficient
implementation (with permission) from Reiserfs.

Date:  Mon Apr  2 11:14:34 PDT 2001
Workarea:  jen.americas.sgi.com:/src/lord/xfs-linux.2.4

The following file(s) were checked into:
  bonnie.engr.sgi.com:/isms/slinx/2.4.x-xfs


Modid:  2.4.x-xfs:slinx:91391a
linux/fs/xfs/xfs_buf_item.c - 1.112
        - Move to a more efficient function to find a bit set in a stream of
          bytes. Code taken from the reiserfs base (I did ask Chris Mason).