Change the type of displayId to int32_t

Change the type of the displayId declaration for the Motion event during injection to int32_t.

Bug: none
Test: build

Change-Id: I3526893773c534aa1a0b87137f38d702a69e05ab

Author: Linnan Li

services/inputflinger/dispatcher/InputDispatcher.cpp

@@ -4680,7 +4680,7 @@ InputEventInjectionResult InputDispatcher::injectInputEvent(const InputEvent* ev
             const bool isPointerEvent =
                     isFromSource(event->getSource(), AINPUT_SOURCE_CLASS_POINTER);
             // If a pointer event has no displayId specified, inject it to the default display.
-            const uint32_t displayId = isPointerEvent && (event->getDisplayId() == ADISPLAY_ID_NONE)
+            const int32_t displayId = isPointerEvent && (event->getDisplayId() == ADISPLAY_ID_NONE)
                     ? ADISPLAY_ID_DEFAULT
                     : event->getDisplayId();
             int32_t flags = motionEvent.getFlags();