xfs: Nuke XFS_ERROR macro

xfs: Nuke XFS_ERROR macro

XFS_ERROR was designed long ago to trap return values, but it's not
runtime configurable, it's not consistently used, and we can do
similar error trapping with ftrace scripts and triggers from
userspace.

Just nuke XFS_ERROR and associated bits.

Port of kernel commit b474c7ae4395ba684e85fde8f55c8cf44a39afaf
from Eric Sandeen.

Signed-off-by: Dave Chinner <dchinner@redhat.com>