graphics: remove duplicated types

Remove duplicated types from allocator@2.0 and composer@2.1.  Those types
are now in common@1.0.

Bug: 32238126
Test: builds and boots
Change-Id: Ibdb907e47969f5a5a98a14a2e2b77a9c5880beff
diff --git a/graphics/allocator/2.0/IAllocator.hal b/graphics/allocator/2.0/IAllocator.hal
index ff08a7e..0464bcd 100644
--- a/graphics/allocator/2.0/IAllocator.hal
+++ b/graphics/allocator/2.0/IAllocator.hal
@@ -16,6 +16,8 @@
 
 package android.hardware.graphics.allocator@2.0;
 
+import android.hardware.graphics.common@1.0::PixelFormat;
+
 interface IAllocator {
     enum Capability : int32_t {
         /* reserved */