linker: Fix off-by-one error implicit array sizing

Arrays are zero based.  If the highest element accessed is 6, the
array needs to have 7 elements.

Fixes piglit test glsl-fs-implicit-array-size-03 and bugzilla #34198.

NOTE: This is a candidate for the 7.9 and 7.10 branches.

src/glsl/linker.cpp

@@ -926,7 +926,7 @@ link_intrastage_shaders(void *mem_ctx,
 	    if (var->type->is_array() && (var->type->length == 0)) {
 	       const glsl_type *type =
 		  glsl_type::get_array_instance(var->type->fields.array,
-						var->max_array_access);
+						var->max_array_access + 1);
 
 	       assert(type != NULL);
 	       var->type = type;