[AArch64][FPenv] Update chain of int to fp conversion

Summary:
When using strict fp, it is required to update the
chain when performing integer type promotion of a
operand to a integer to floating point conversion.

Reviewers: craig.topper, john.brawn

Reviewed By: craig.topper

Subscribers: kristof.beyls, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74597