[MVT] Add missing floating point types for 1024/2048-bit vectors.

Summary:
This patch adds entries for:
  v64f16
  v128f16
  v64bf16
  v128bf16
  v32f64

Subscribers: dschuff, hiraditya, aheejin, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D82466