ipxact: cv32a6 converted into IPXACT 1685-2014 version

Created by: frikhaAziz

I converted the file to the latest version of IPXACT 1685-2014. I added fields in sstatus and mstatus registers RFU (WPRI) according to riscv-privileged. I proposed a new format of vendor extension to describe the privilege of CSR registers. I proposed a new format of vendor extension to describe the RISCV behavior (WPRI, WARL, WLRL) by adding a list for legal values (WLRL,WARL) and a list for read values (WPRI).