[llvm] [AArch64][GISel] Assign registers into FPR if they feed into FP instructions indirectly via PHI (PR #94618)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

Maybe `case TargetOpcode::G_LOAD: `needs some special treatment for phis.

https://github.com/llvm/llvm-project/pull/94618