Fetch country code information from Device sysfs path

HID devices report the country code via sysfs. Need to read it
and pass it and save it as a member variable to InputDevice

In subsequent CLs will use it to auto-detect a layout for PK.
More information in DD: go/pk_auto_layout_detection

Test: atest inputflinger_tests:InputReaderTest
Bug: 242715614
Change-Id: I73ca7518dbee3e563c41024bb3ed41261c8d7846
diff --git a/services/inputflinger/reader/include/InputDevice.h b/services/inputflinger/reader/include/InputDevice.h
index 51872ac..141464f 100644
--- a/services/inputflinger/reader/include/InputDevice.h
+++ b/services/inputflinger/reader/include/InputDevice.h
@@ -158,6 +158,7 @@
     int32_t mId;
     int32_t mGeneration;
     int32_t mControllerNumber;
+    hardware::input::InputDeviceCountryCode mCountryCode;
     InputDeviceIdentifier mIdentifier;
     std::string mAlias;
     ftl::Flags<InputDeviceClass> mClasses;
@@ -311,6 +312,9 @@
     }
 
     inline std::vector<TouchVideoFrame> getVideoFrames() { return mEventHub->getVideoFrames(mId); }
+    inline hardware::input::InputDeviceCountryCode getCountryCode() const {
+        return mEventHub->getCountryCode(mId);
+    }
     inline int32_t getScanCodeState(int32_t scanCode) const {
         return mEventHub->getScanCodeState(mId, scanCode);
     }