sdm: Conditionally revert "sdm: Implement ‘Null Display’ in SDM core"

This commit conditionally reverts the add of the member function
`IsDisplayHWAvailable()` from commit
24255680b2c02c809040594c8e7536837118754d.

Change-Id: I9ea381906e98134069993e91429594c59d17efc3
diff --git a/sdm/include/private/resource_interface.h b/sdm/include/private/resource_interface.h
index c68e77a..e95eb9a 100644
--- a/sdm/include/private/resource_interface.h
+++ b/sdm/include/private/resource_interface.h
@@ -143,7 +143,9 @@
   virtual uint32_t GetMixerCount() = 0;
   virtual void HandleTUITransition(Handle display_ctx, bool tui_active) = 0;
   virtual DisplayError SetBlendSpace(Handle display_ctx, const PrimariesTransfer &blend_space) = 0;
+#ifdef SDMCORE_HAS_IS_DISPLAY_HW_AVAILABLE_FUNC
   virtual bool IsDisplayHWAvailable() = 0;
+#endif
 };
 
 }  // namespace sdm
diff --git a/sdm/libs/core/Android.bp b/sdm/libs/core/Android.bp
index ef10e8e..683066a 100644
--- a/sdm/libs/core/Android.bp
+++ b/sdm/libs/core/Android.bp
@@ -1,6 +1,9 @@
 cc_library_shared {
     name: "libsdmcore",
-    defaults: ["qtidisplay_defaults"],
+    defaults: [
+        "qtidisplay_defaults",
+        "sdmcore_has_is_display_hw_available_func_defaults",
+    ],
     sanitize: {
         integer_overflow: true,
     },
diff --git a/sdm/libs/core/comp_manager.cpp b/sdm/libs/core/comp_manager.cpp
old mode 100755
new mode 100644
index b2812ee..7f14600
--- a/sdm/libs/core/comp_manager.cpp
+++ b/sdm/libs/core/comp_manager.cpp
@@ -811,12 +811,16 @@
 }
 
 bool CompManager::IsDisplayHWAvailable() {
+#ifdef SDMCORE_HAS_IS_DISPLAY_HW_AVAILABLE_FUNC
   std::lock_guard<std::recursive_mutex> obj(comp_mgr_mutex_);
   if (resource_intf_) {
     return resource_intf_->IsDisplayHWAvailable();
   }
 
   return false;
+#else
+  return true;
+#endif
 }