Add the following instructions:

* vl<nf>re<eew>.v
* vs<nf>r.v

Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20211210075704.23951-25-frank.chang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>