gdb/NEWS: mention DWP v1 support removal

Support for DWP v1 was removed in commit 92a222b648d ("gdb/dwarf: remove
support for DWP v1").

Change-Id: I6ce341bb6a2238b434fb458b3e2aa81db74cd8ae
Approved-By: Eli Zaretskii <eliz@gnu.org>
1 file changed