Remove gfxstream stub modules that conflict with stock mesa3d

The stub modules (mesa_platform_virtgpu_defaults, vulkan.ranchu,
gfxstream_defaults, libgfxstream_backend, mesa_gfxstream_guest_iostream,
mesa_gfxstream_connection_manager) were defined for cuttlefish/emulator
compatibility but create module-name collisions with stock
platform/external/mesa3d. These stubs are not needed on a physical
RK3588 device. All real mesa modules (libEGL_mesa, libgallium_dri, etc.)
have unique names that don't conflict with stock.

Copyright (C) 2026 Brendan Szymanski <hello@bscubed.dev>

Android.bp

@@ -4081,49 +4081,3 @@ cc_defaults {
     static_libs: ["libperfetto_client_experimental"],
 }
 
-// Stub defaults module for gfxstream compatibility (emulator code not used on real hardware)
-cc_defaults {
-    name: "mesa_platform_virtgpu_defaults",
-    cflags: [
-        "-DUSE_VIRTGPU=0",
-    ],
-}
-
-// Stub module for cuttlefish/emulator compatibility (not used on real hardware)
-cc_library_shared {
-    name: "vulkan.ranchu",
-    srcs: [],
-    shared_libs: [],
-}
-
-// Stub modules for gfxstream compatibility (emulator code not used on real hardware)
-cc_defaults {
-    name: "gfxstream_defaults",
-    cflags: [
-        "-DGFXSTREAM_STUB=1",
-    ],
-}
-
-cc_library_shared {
-    name: "libgfxstream_backend",
-    srcs: [],
-    target: {
-        host: {
-            enabled: true,
-            srcs: [],
-        },
-        android: {
-            enabled: true,
-        },
-    },
-}
-
-cc_library_static {
-    name: "mesa_gfxstream_guest_iostream",
-    srcs: [],
-}
-
-cc_library_static {
-    name: "mesa_gfxstream_connection_manager",
-    srcs: [],
-}