Integrate new result macros. (#1780)

* result: try out some experimental shenanigans

* result: sketch out some more shenanigans

* result: see what it looks like to convert kernel to use result conds instead of guards

* make rest of kernel use experimental new macro-ing

libraries/libmesosphere/source/kern_k_io_pool.cpp

@@ -80,7 +80,7 @@ namespace ams::kern {
         m_pool_type      = pool_type;
         m_is_initialized = true;
 
-        return ResultSuccess();
+        R_SUCCEED();
     }
 
     void KIoPool::Finalize() {
@@ -113,7 +113,7 @@ namespace ams::kern {
         /* Add the region to our pool. */
         m_io_region_list.push_back(*new_region);
 
-        return ResultSuccess();
+        R_SUCCEED();
     }
 
     void KIoPool::RemoveIoRegion(KIoRegion *region) {