trace: Don't immediately destroy the pipe's sampler view in the trace driver.

trace: Don't immediately destroy the pipe's sampler view in the trace driver.

The trace driver's implementation of sampler_view_destroy was calling
directly into the underlying pipe's sampler_view_destroy implementation.
This causes problems for pipes that keep references to sampler views
even after the state tracker has released them.  Instead, we'll simply
drop the trace driver's reference to the pipe's sampler view.

Signed-off-by: José Fonseca <jfonseca@vmware.com>