Revert "cmd/compile,cmd/internal/sys: enable additional build modes on linux/riscv64"
This reverts CL 263457.
It turns out that this still missed changes to cmd/link/internal/ld/config.go
and some of these build modes also fail once cgo is enabled. Disable again for
now.
Change-Id: Iaf40d44e1551afd5b040d357f04af134f55a64a9
Reviewed-on: https://go-review.googlesource.com/c/go/+/266317 Reviewed-by: Cherry Zhang <cherryyz@google.com>
Trust: Joel Sing <joel@sing.id.au>