glsl: Use typed foreach_in_list_safe instead of foreach_list_safe.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 8bb1104..d588bc6 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -1078,9 +1078,7 @@
       temps = hash_table_ctor(0, hash_table_pointer_hash,
 			      hash_table_pointer_compare);
 
-   foreach_list_safe(node, instructions) {
-      ir_instruction *inst = (ir_instruction *) node;
-
+   foreach_in_list_safe(ir_instruction, inst, instructions) {
       if (inst->as_function())
 	 continue;