feat: power down dGPUs on hybrid graphics laptops

kernel/src/ACPI/AML/AmlNamespace.cpp

@@ -89,6 +89,10 @@ namespace Hal {
                 s_transientNext = 0;
             }
 
+            bool IsPersistent(int32_t index) {
+                return index > 0 && index <= MaxPersistent;
+            }
+
             static Entry* Lookup(int32_t index) {
                 if (index <= 0) return nullptr;
                 int32_t i = index - 1;
@@ -293,6 +297,12 @@ namespace Hal {
             return -1;
         }
 
+        int32_t Namespace::FindChild(int32_t parentIndex, const char* seg) const {
+            char padded[MaxNameSegLen + 1];
+            PadSegment(seg, padded);
+            return FindChildByName(parentIndex, padded);
+        }
+
         int32_t Namespace::CreateNode(const char* absolutePath) {
             EnsureRoot();
             char segments[MaxPathDepth][MaxNameSegLen + 1];