vgsp-sema: drain the injection queue immediately before the GR fill (second-client zeros)

The watcher's pins for the second client's a/b/c buffers can land between
the service loop's svc_handle_map_add() and the launch capture; the fill
then misses them via svc_ipin_lookup, resolves 0 pages, relocates nothing,
and the win0 param page keeps the driver's guest VAs (rk1: candidate[0..2]
-> 0 new pages; DIAG win0[0] 160=753e4ec00000). Drain the queue right
before svc_gr_req_fill() (same service thread, no race).

0 files changed, 0 insertions, 0 deletions