llvm: stop generating FPU code if there is no FPU

Fixes #14465

For aarch64, LLVM was crashing because Zig commands it to generate FPU code
even when there is no FPU present. This commit implements the necessary checks
to avoid this undesired situation and aarch64 can be compiled again with
no FPU.

Author: David Gonzalez Martin

src/codegen/llvm.zig

@@ -11165,6 +11165,7 @@ fn backendSupportsF16(target: std.Target) bool {
         .mips64,
         .mips64el,
         => false,
+        .aarch64 => std.Target.aarch64.featureSetHas(target.cpu.features, .fp_armv8),
         else => true,
     };
 }
@@ -11175,6 +11176,7 @@ fn backendSupportsF16(target: std.Target) bool {
 fn backendSupportsF128(target: std.Target) bool {
     return switch (target.cpu.arch) {
         .amdgcn => false,
+        .aarch64 => std.Target.aarch64.featureSetHas(target.cpu.features, .fp_armv8),
         else => true,
     };
 }