libaudiohal@aidl: Remove non-working code for HAL PIDs retrieval

Since native audio_server does not have "list services" permission,
it is always being denied to get services debug info (which includes
PIDs). Effectively, `DevicesFactoryHalAidl::getHalPids` never works.
The job of retrieval of HAL PIDs is actually done by the Java
AudioService. The code in libaudiohal@aidl triggers an SELinux
denial and thus should be removed.

Bug: 314853580
Test: check kernel log for 'avc:  denied  { list }'
Test: DeviceBootTest
(cherry picked from commit db666111308159850ae94fd4bcbc1b7c4d091dcd)
Change-Id: I5fb8e0a98a49141ec488e4faa04274eba46f80fa
diff --git a/media/libaudiohal/impl/DevicesFactoryHalAidl.cpp b/media/libaudiohal/impl/DevicesFactoryHalAidl.cpp
index a8f9f7e..96a3e60 100644
--- a/media/libaudiohal/impl/DevicesFactoryHalAidl.cpp
+++ b/media/libaudiohal/impl/DevicesFactoryHalAidl.cpp
@@ -24,7 +24,6 @@
 
 #include <aidl/android/hardware/audio/core/IModule.h>
 #include <android/binder_manager.h>
-#include <binder/IServiceManager.h>
 #include <media/AidlConversionNdkCpp.h>
 #include <media/AidlConversionUtil.h>
 #include <utils/Log.h>
@@ -119,23 +118,9 @@
     if (pids == nullptr) {
         return BAD_VALUE;
     }
-    // The functionality for retrieving debug infos of services is not exposed via the NDK.
-    sp<IServiceManager> sm = defaultServiceManager();
-    if (sm == nullptr) {
-        return NO_INIT;
-    }
-    std::set<pid_t> pidsSet;
-    const auto moduleServiceName = std::string(IModule::descriptor) + "/";
-    auto debugInfos = sm->getServiceDebugInfo();
-    for (const auto& info : debugInfos) {
-        if (info.pid > 0 &&
-                info.name.size() > moduleServiceName.size() && // '>' as there must be instance name
-                info.name.substr(0, moduleServiceName.size()) == moduleServiceName) {
-            pidsSet.insert(info.pid);
-        }
-    }
-    *pids = {pidsSet.begin(), pidsSet.end()};
-    return NO_ERROR;
+    // Retrieval of HAL pids requires "list services" permission which is not granted
+    // to the audio server. This job is performed by AudioService (in Java) instead.
+    return PERMISSION_DENIED;
 }
 
 status_t DevicesFactoryHalAidl::setCallbackOnce(sp<DevicesFactoryHalCallback> callback) {