libexif: Avoid buffer overflow due to compiler optimization am: ba7f703b28 am: 62e2456a62

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/libexif/+/12828416

Change-Id: Ic2ed7b0d1573e378fbc5c168a2d6ddbe56be6f9c