TAKE - remove remains of internal readahead state from xfs

[Steve Lord <lord@sgi.com>]

Readahead is handled at the vfs layer, this is dead code.

Date:  Wed Mar  6 11:58:25 PST 2002
Workarea:  jen.americas.sgi.com:/src/lord/xfs-merge.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:113419a
linux/fs/xfs/xfs_macros.c - 1.39
	- remove readahead reset macro - dead code

linux/fs/xfs/xfs_vnodeops.c - 1.517
	- remove readahead reset macro calls, and iocore_reset calls - the latter
	  did nothing and we were obtaining a lock to do it.

linux/fs/xfs/xfs_iocore.c - 1.27
	- remove xfs_iocore_reset - it was dead code

linux/fs/xfs/xfs_inode.h - 1.156
	- remove internal readahead reset macro, not used

linux/fs/xfs/linux/xfs_lrw.c - 1.126
	- remove internal readahead reset - not used