Update x/sys module to support Risc-V

[carlosedp]

Updating projects using libraries that were recently updated to support Risc-V.

Go upstream work is tracked on: golang/go#27532

Risc-V software support tracker on https://github.com/carlosedp/riscv-bringup

[codecov-io]

Codecov Report

Merging #32 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #32   +/-   ##
=======================================
  Coverage   58.88%   58.88%           
=======================================
  Files           6        6           
  Lines         518      518           
=======================================
  Hits          305      305           
  Misses        210      210           
  Partials        3        3

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