mhvtl.spec: Update for 1.4-5_release

The most important bug fix is an EOM (End of Media) handling on some emulations.
The symptom was backup software typically failed when spanning media
(block count was off by one).

Fix returned data from TAPE CAPACITY log page (byte swap issue).

Add LTO-6 emulation.

Signed-off-by: Mark Harvey <markh794@gmail.com>