cmd/internal/obj: ARM64 uses beyond 12k
cmd/internal/obj: ARM64 uses beyond 12k

Its range actually extends beyond 13k, so extend it all the way up to
16k.

Change-Id: Iad3281695d2e84b8895637ed274e447b36358f76

mgyenik/go,mgyenik/go,mgyenik/go,mgyenik/go,mgyenik/go,mgyenik/go,mgyenik/go,mgyenik/go