stdlib: Add missing @overrides to RISCVBoard

Change-Id: I6879c9744c28038c5d40984785f2f502a2fd1c5a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52185
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed