nir: Move zero_initialize_shared_memory into common shader_info

Move it out the "cs" sub-struct, since the bit will be used for other
shader stages in the future.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11225>

src/compiler/shader_info.h

@@ -254,6 +254,11 @@ typedef struct shader_info {
     */
    bool shared_memory_explicit_layout:1;
 
+   /**
+    * Used for VK_KHR_zero_initialize_workgroup_memory.
+    */
+   bool zero_initialize_shared_memory:1;
+
    union {
       struct {
          /* Which inputs are doubles */
@@ -396,8 +401,6 @@ typedef struct shader_info {
           */
          enum gl_derivative_group derivative_group:2;
 
-         bool zero_initialize_shared_memory;
-
          /**
           * pointer size is:
           *   AddressingModelLogical:    0    (default)