Preemptive imports to avoid conflicts from AOSP

This is just a minimal staging of go/oag/topic:"imapper5"
to handle the difference between AOSP's graphics-common
and internal's graphics-common

Test: make
Change-Id: I6fbc22272ba95b44aa09ff08f9d9a7adbb9ae8be
diff --git a/graphics/allocator/aidl/Android.bp b/graphics/allocator/aidl/Android.bp
index 272ab48..cd4885b 100644
--- a/graphics/allocator/aidl/Android.bp
+++ b/graphics/allocator/aidl/Android.bp
@@ -17,6 +17,7 @@
     srcs: ["android/hardware/graphics/allocator/*.aidl"],
     imports: [
         "android.hardware.common-V2",
+        "android.hardware.graphics.common-V4",
     ],
     stability: "vintf",
     backend: {