makefs: correct iso9660 Rock Ridge TF timestamps

[emaste]

Summary

The bit definitions for the TF_* timestamp bits (TF_MODIFY, etc.) were
incorrect, and timestamps were written in the wrong order.

See RRIP 4.1.6 Description of the "TF" System Use Entry for details.

PR:             203531

[jrtc27]

This matches my reading of the spec

[emaste]

usr.sbin/makefs/cd9660/iso9660_rrip.h

63–65

these don't make sense - the first two are not used, the third is p->attr.rr_entry.NM.flags[0] = (unsigned char) NM_PARENT; (i.e., 0x200 cast to a byte)

to be dealt with later