xfs: Remove the obsolete XLOG_CIL_HARD_SPACE_LIMIT() macros

There is no more users of this Macro, so it's time to kill it dead.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>