re PR go/87661 (libgo bootstrap failure on arm-linux-gnueabihf (redefinition of constants))

	PR go/87661
    runtime: remove unused armArch, hwcap and hardDiv
    
    After CL 140057 these are only written but never read in gccgo.
    
    Reviewed-on: https://go-review.googlesource.com/c/141077

From-SVN: r265439