nir: Make nir_ssa_def_rewrite_uses take an SSA value

This commit replaces the new_src parameter of nir_ssa_def_rewrite_uses()
with an SSA def, removes nir_ssa_def_rewrite_uses_ssa(), and rewrites
all the users as needed.

Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Acked-by: Alyssa Rosenzweig <alyssa@collabora.com>
Acked-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9383>

src/compiler/glsl/gl_nir_lower_buffers.c

@@ -220,7 +220,7 @@ lower_buffer_interface_derefs_impl(nir_function_impl *impl,
             cast->cast.align_offset = offset % NIR_ALIGN_MUL_MAX;
 
             nir_ssa_def_rewrite_uses(&deref->dest.ssa,
-                                     nir_src_for_ssa(&cast->dest.ssa));
+                                     &cast->dest.ssa);
             nir_deref_instr_remove_if_unused(deref);
             break;
          }