This patch adds half-precision FP conversion instructions extending support of full-precision variants in v8.0.
FCVTMU <Hd>.<Ts>, <Hn>.<Ts>
FCVTNU <Hd>.<Ts>, <Hn>.<Ts>
FCVTZS <Hd>.<Ts>, <Hn>.<Ts>
FCVTZS <Wd>, <Hn>
FCVTZS <Xd>, <Hn>
FCVTZS <Wd>, <Hn>, #<fbits>
FCVTZS <Xd>, <Hn>, #<fbits>
FCVTZS <Hd>, <Hn>
FCVTZU <Hd>.<Ts>, <Hn>.<Ts>
FCVTZU <Wd>, <Hn>
FCVTZU <Xd>, <Hn>
FCVTZU <Wd>, <Hn>, #<fbits>
FCVTZU <Xd>, <Hn>, #<fbits>
FCVTZU <Hd>, <Hn>Issue: #2626