svga: use pipe_sampler_view::target in svga_set_sampler_views()

svga: use pipe_sampler_view::target in svga_set_sampler_views()

instead of the underlying texture's target.  This fixes an issue
where the TGSI sampler type was not agreeing with the sampler view
target/type.  In particular, this fixes a Mint 19 XFCE desktop
scaling issue because the TGSI code was using a RECT sampler but
the sampler view's underlying texture was PIPE_TEXTURE_2D.

We want to use the sampler view's type rather than the underlying
resource, as we do for the view's surface format.

No piglit regressions.

VMware issue 2156696.

Reviewed-by: Neha Bhende <bhenden@vmware.com>
Reviewed-by: Charmaine Lee <charmainel@vmware.com>