fixes some (not all) buffer overreads during decoding pentax makernote entries. am: 836cfdb99e am: 0a45dca22e am: 24bdc1361a am: 8e051e1ef6 am: 3dcd0f5c7e am: 514b69b2a6 am: 2769ec9913 am: cd54138907

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/libexif/+/12970376

Change-Id: I7f065d30b9df7a5d9d6f45b263159d4c08b47778