Delete outdated note about vector crypto (riscv#1573)

Resolves riscv#1572

src/scalar-crypto.adoc

@@ -33,12 +33,6 @@ This is found in <<crypto_scalar_es>>.
 It also contains a mechanism allowing core implementers to provide
 _"Constant Time Execution"_ guarantees in <<crypto_scalar_zkt>>.
 
-A companion document _Volume II: Vector Instructions_, describes
-instruction proposals which build on the RISC-V Vector Extension.
-The Vector Cryptography extension is currently a work in progress
-waiting for the base Vector extension to stabilise.
-We expect to pick up this work in earnest in Q4-2021 or Q1-2022.
-
 [[crypto_scalar_audience]]
 ==== Intended Audience