[PowerPC][Power10] Implement Parallel Bits Deposit/Extract Builtins in LLVM/Clang

This patch implements builtins for the following prototypes:

vector unsigned long long vec_pdep(vector unsigned long long, vector unsigned long long);
vector unsigned long long vec_pext(vector unsigned long long, vector unsigned long long __b);
unsigned long long __builtin_pdepd (unsigned long long, unsigned long long);
unsigned long long __builtin_pextd (unsigned long long, unsigned long long);

Revision Depends on D80758

Differential Revision: https://reviews.llvm.org/D80935