be: Provide an inline implementation of arch_add_irn_flags().

ir/be/bearch.c

@@ -96,12 +96,6 @@ void arch_set_irn_register(ir_node *node, const arch_register_t *reg)
 	out->reg = reg;
 }
 
-void arch_add_irn_flags(ir_node *node, arch_irn_flags_t flags)
-{
-	backend_info_t *const info = be_get_info(node);
-	info->flags |= flags;
-}
-
 bool arch_reg_is_allocatable(const arch_register_req_t *req,
                              const arch_register_t *reg)
 {

ir/be/bearch.h

@@ -157,7 +157,11 @@ static inline arch_irn_flags_t arch_get_irn_flags(const ir_node *node)
 	return info->flags;
 }
 
-void arch_add_irn_flags(ir_node *node, arch_irn_flags_t flags);
+static inline void arch_add_irn_flags(ir_node *const node, arch_irn_flags_t const flags)
+{
+	backend_info_t *const info = be_get_info(node);
+	info->flags |= flags;
+}
 
 /**
  * Returns true if the given node should not be scheduled (has