Fix mac build: cast fpr callee save addresses.

Bring back reinterpret_cast<>s removed by
    https://android-review.googlesource.com/151309 .
They are needed for mac builds.

Bug : 13925192

(cherry picked from commit 0eb42511405f3919572a480a009426dfb776cfb5)

Change-Id: If6e0cdbadcc84a046abe03d7eca5cccd0a50d141
2 files changed