svga: emit sampler declarations in the helper function for non vgpu10

svga: emit sampler declarations in the helper function for non vgpu10

With commit dc9ecf58c0c5c8a97cd41362e78c2fcd9f6e3b80,
we are now getting the sampler target from the sampler view
declaration. But since a sampler view declaration can be defined
after a sampler declaration, we need to emit the
sampler declarations in the pre-helpers function, otherwise,
the sampler target might not have defined yet for the sampler declaration.

Fixes viewperf maya-03 and various gl trace regressions in hwv11.

Reviewed-by: Brian Paul <brianp@vmware.com>