Make Regs*::Read parameter const. am: a9a7faddda

Original change: https://android-review.googlesource.com/c/platform/system/unwinding/+/2944725

Change-Id: Id7b947bb170b7398c9fecbf10f1323200522b282
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>