Fix lint warnings under com.android.server.inputmethod

This is a mechanical style-fix CL with no behavior change.

Fix: 249790290
Test: prebuilts/checkstyle/checkstyle.py -f \
  frameworks/base/services/core/java/com/android/server/inputmethod/ \
  | grep ".java:"
Change-Id: I64326fa2bec0293ecf0c62e4380bafa98c694721