[committed] Define extra_parts on hppa*64*-*-linux* and hppa*-*-linux*

[John David Anglin]

The hppa*-*-linux* targets don't support libvtv.  The default linux  
define for extra_parts now includes
vtv_start.o vtv_end.o vtv_start_preinit.o and vtv_end_preinit.o.   
These are not built and cause
extraneous install warnings.

Tested on both targets and committed to trunk.

Dave
--
John David Anglin	dave.anglin@bell.net