TAKE - Crash diet for xfs stack usage.

[Eric Sandeen <sandeen@sgi.com>]

linvfs_remount and linvfs_read_super had the humongous xfs_args
struct on the stack; allocate it instead.

Also, since I've been looking at xfs_bmapi() anyway, and it has fairly
high stack usage, trim down one of the structs it puts on the stack.

Date:  Tue Jul  9 13:20:34 PDT 2002
Workarea:  stout.americas.sgi.com:/localhome/src/sandeen/2.4.x-xfs/workarea-alwaysclean

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


Modid:  2.4.x-xfs:slinx:122728a
linux/fs/xfs/xfs_bmap.h - 1.77
linux/fs/xfs/xfs_bmap.c - 1.285
	- Change xfs_bmalloca_t to use chars instead of ints to reduce
	  stack usage; fix up associated functions.

linux/fs/xfs/linux/xfs_super.c - 1.187
	- Ease up on stack; allocate xfs_args struct for linvfs_read_super
	  and linvfs_remount