[RISCV] Add support for XCVbitmanip extension in CV32E40P

Implement XCVbitmanip intrinsics for CV32E40P according to the specification.

This commit is part of a patch-set to upstream the 7 vendor specific extensions of CV32E40P.

Contributors: @CharKeaney, @jeremybennett, @lewis-revill, @liaolucy, @simoncook, @xmj.

Spec: https://github.com/openhwgroup/cv32e40p/blob/62bec66b36182215e18c9cf10f723567e23878e9/docs/source/instruction_set_extensions.rst

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D152915