scsiata.cpp: Add class usbprolific_device to support Prolific PL2773
USB bridges (ticket #482).
smartctl.8.in, smartd.conf.5.in: Document '-d usbprolific'.

Patch was provided by Tommy Vestermark.

git-svn-id: https://svn.code.sf.net/p/smartmontools/code/trunk/smartmontools@4004 4ea69e1a-61f1-4043-bf83-b5c94c648137
Update NEWS.

git-svn-id: https://svn.code.sf.net/p/smartmontools/code/trunk/smartmontools@4005 4ea69e1a-61f1-4043-bf83-b5c94c648137