target/riscv/kvm: remove sneaky strerrorname_np() instance

target/riscv/kvm: remove sneaky strerrorname_np() instance

Commit d424db2354 excluded some strerrorname_np() instances because they
break musl libc builds. Another instance happened to slip by via commit
d4ff3da8f4.

Remove it before it causes trouble again.

Fixes: d4ff3da8f4 (target/riscv/kvm: initialize 'vlenb' via get-reg-list)
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
(cherry picked from commit e4426353175f21f54095701c704ba4c50724cb80)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>