Move displayid into InputEvent

There are certain use cases where key events should be associated with a
particular display. Refactor KeyEvent and MotionEvent to have an
associated display id.

Remove "hasAssociatedDisplay" variable from KeyboardInputMapper,
it just used to mirror "isOrientationAware".

If the keyboard is orientation aware (= it is physically attached to a
display, and therefore rotates together with that display), then
associate that keyboard with the internal viewport. Otherwise, the key
events are not associated with any particular display.

Remaining to do:
- make mInternalDisplay, mExternalDisplay, mVirtualDisplays into a
single vector with type (internal, external, virtual)
- have getDisplayViewport return std::optional (will require deep
changes)

Bug: 64258305
Test: atest inputflinger_tests libinput_tests

Change-Id: I4fe145e74cb59310efaa55bfc9dc3c2b3bd997e3
diff --git a/include/input/InputTransport.h b/include/input/InputTransport.h
index ee52661..e8d1345 100644
--- a/include/input/InputTransport.h
+++ b/include/input/InputTransport.h
@@ -64,6 +64,7 @@
             nsecs_t eventTime __attribute__((aligned(8)));
             int32_t deviceId;
             int32_t source;
+            int32_t displayId;
             int32_t action;
             int32_t flags;
             int32_t keyCode;
@@ -211,6 +212,7 @@
             uint32_t seq,
             int32_t deviceId,
             int32_t source,
+            int32_t displayId,
             int32_t action,
             int32_t flags,
             int32_t keyCode,