Remove an obsolete comment about BridgeIInputMethodManager

BridgeIInputMethodManager has been removed [1].

 [1]: I6cc2ec078230064fcce3656788589af59a1f7e2d
      116000a4c644ddd562efeb1ee549909be0d7b332

Bug: 27297992
Test: compile
Change-Id: Iba6e1bb90c92692ab16ab2dd9d83665fe7e1c48c
1 file changed