Add FP16ALT support to THMULTI DivSqrt
Created by: lucabertaccini
This PR adds FP16ALT support to THMULTI DivSqrt units.
The modifications are condensed in a vendor patch so that a ./util/vendor.py vendor/openc910.vendor.hjson --update
would produce the same code base as in vendor/openc910
. An alternative approach could be forking the openc910 repo, implementing the modifications there, and vendorizing the forked repo instead.