xfs: print useful caller information in xfs_error_report

xfs_error_report used to just print the hex address of the caller;
%pF will give us something more human-readable.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>