glsl: Replace most default cases in switches on GLSL type

This makes it easier to find switch-statements that need to be updated
after a new GLSL_TYPE_* is added because the compiler will generate a
warning.

Switch-statements that only had a small number of cases (e.g.,
everything in ir_constant_expression.cpp) were not modified.  I may
regret that decision when we eventually add support for doubles.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Carl Worth <cworth@cworth.org>
Reviewed-by: Chad Versace <chad.versace@linux.intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/program/ir_to_mesa.cpp

@@ -623,10 +623,13 @@ type_size(const struct glsl_type *type)
        * at link time.
        */
       return 1;
-   default:
-      assert(0);
-      return 0;
+   case GLSL_TYPE_VOID:
+   case GLSL_TYPE_ERROR:
+      assert(!"Invalid type in type_size");
+      break;
    }
+
+   return 0;
 }
 
 /**
@@ -2529,7 +2532,10 @@ _mesa_associate_uniform_storage(struct gl_context *ctx,
 	    format = uniform_native;
 	    columns = 1;
 	    break;
-	 default:
+         case GLSL_TYPE_ARRAY:
+         case GLSL_TYPE_VOID:
+         case GLSL_TYPE_STRUCT:
+         case GLSL_TYPE_ERROR:
 	    assert(!"Should not get here.");
 	    break;
 	 }