cmd/internal/obj/arm64: use appropriate return type for regoff
All of the callers of regoff cast the return value from uint32 to int32.
Instead, simply return int32 in the first place.
Change-Id: I43a672bb3143a71f4a37779ed8ae9adcda623ba4
Reviewed-on: https://go-review.googlesource.com/c/go/+/490355
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>